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Publication No. 048R212-000Issue 7, January 1997

OPERATING AND INSTALLATION INSTRUCTIONSFOR

DataComm 500F/AXRDATA SERVICE UNIT

General DataComm, Inc.MIDDLEBURY, CONNECTICUT06762-1299

ATTENTION!STATIC SENSITIVE DEVICES

PROPER HANDLING AND GROUNDINGPRECAUTIONS REQUIRED

This equipment contains electrostatic sensitive devices. Use ESD precautionaryprocedures when removing or inserting parts or printed circuit (pc) cards. Keep partsand pc cards in their antistatic packaging material until ready to install.

The use of an antistatic wrist strap, connected to the grounded equipment frame orchassis, is recommended when handling pc cards during installation, removal, orsetting of on-board option switches. Do not use a conductive tool, such as a screwdriveror paper clip, to set the position of the option switches.

INSTALLATION SAFETY INSTRUCTIONS

a. Never install telephone wiring during a lightning storm.

b. Never install telephone jacks in a wet location unless the jack is specificallydesigned for wet locations.

c. Never touch uninsulated telephone wires or terminals unless the telephone line hasbeen disconnected at the network interface.

d. Use caution when installing or modifying telephone lines.

CAUTIONPotentially hazardous voltages exist within this unit.

DataComm 500F/AXRDATA SERVICE UNIT

(GDC PART NOs. 048A062-001, -011, -021,048M062-001, -002, and 048P062-001)

General DataComm, Inc. (GDC)Middlebury, Connecticut 06762-1299

This product was designed and manufactured by

WARNING

This equipment generates, uses, and can radiate radio frequency energy and ifnot installed and used in accordance with the instruction manual, may cause in-terference to radio communications. It has been tested and found to comply withthe limits for a Class A computing device pursuant to Subpart J of Part 15 of FCCRules, which are designed to provide reasonable protection against such interfer-ence when operated in a commercial environment. Operation of this equipment ina residential area is likely to cause interference, in which case the user at hisown expense will be required to take whatever measures may be required to cor-rect the interference.

CRC-REQUIRED NOTIFICATION

This equipment is a Class A digital apparatus which complies with the RadioInterference Regulations, CRC c.1374.

PUBLICATION NOTICE

This manual has been carefully compiled and checked for accuracy. The infor-mation in this manual does not constitute a warranty of performance.Furthermore, GDC reserves the right to revise this publication and make changesfrom time to time in the content thereof. GDC assumes no liability for losses in-curred as a result of out-of-date or incorrect information contained in this man-ual.

READER’S COMMENTS

Comments regarding this manual should be addressed to:

Publications DepartmentGeneral DataComm, Inc.1579 Straits TurnpikeP.O Box 1299Middlebury, Connecticut 06762-1299

PROPRIETARY NOTICE

This publication contains information proprietary and confidential to GeneralDataComm, Inc. Any reproduction, disclosure, or use of this publication is ex-pressly prohibited except as General DataComm, Inc., may otherwise authorize inwriting.

Copyright, General DataComm, Inc., 1992

FCC-REQUIRED NOTIFICATION

FOR USERS OF FCC-REGISTERED EQUIPMENT

Read before using this technical manual or installing subject equipment.

This equipment complies with Part 68 of the Federal Communications Commission (FCC) Rulesand Regulations. Connection of data communication equipment to the public telephone networkis regulated by the FCC Rules and Regulations. These regulations require:

A. To connect the DataComm 500F/AXR to the Public Telephone Network you are required togive the Telephone Company the following information.

1. The FCC Registration Number which is TBD.

2. The FIC (Facility Interface Code) which is 04DU5-24, 04DU5-48, 04DU5-96, 04DU5-56.

3. The SOC (Service Order Code) which is 6.ON.

4. The Telephone Company jack type which is RJ48S.

B. If you experience trouble, disconnect the equipment from the telephone line to determine ifthe equipment is malfunctioning. If it is, remain disconnected until the problem is cor-rected. Should this equipment cause harm to the telephone network, the telephone companymay discontinue your service temporarily. If possible they will notify you in advance. But ifadvance notice is not practical, you will be notified as soon as possible. You will be informedof your right to file a complaint with the FCC.

C. The telephone company may change its communication facilities, equipment, operations,and procedures where reasonably required for operation. If this occurs, the telephone com-pany will notify you in writing.

D. It is the user's obligation to notify the telephone company prior to disconnecting equipmentfrom 1.544 Mbps digital service.

E. According to Part 68 of the FCC Rules and Regulations, customers are not authorized to re-pair or modify this equipment. Any repair or modification will null and void the FCC regis-tration and the warranty of this equipment.

Rev. 3, January 1992

TABLE OF CONTENTS

Section &Subject Page

1 — INTRODUCTION

DataComm 500F/AXR FEATURES .........................................................................................................................1-1

DESCRIPTION .........................................................................................................................................................1-1

DIAGNOSTICS .........................................................................................................................................................1-1

SERVICE AND TRAINING .....................................................................................................................................1-2

2 — INSTALLATION

OVERVIEW...............................................................................................................................................................2-1

UNPACKING AND HANDLING .............................................................................................................................2-1

PREOPERATIONAL CHECK.................................................................................................................................. 2-1

Checking Option Selection .....................................................................................................................................2-1

Checking the Installation and Line .......................................................................................................................2-1

Transposed Lines ...................................................................................................................................................2-1

Changes in Service Rate.........................................................................................................................................2-1

INSTALLATION PROCEDURES............................................................................................................................ 2-2

Standalone Installation.......................................................................................................................................... 2-2

Rackmount Installation .........................................................................................................................................2-2

OPTION SELECTION .............................................................................................................................................2-2

ELECTRICAL CONNECTIONS.............................................................................................................................. 2-8

Standalone Enclosure.............................................................................................................................................2-8

Rackmount Shelf .................................................................................................................................................... 2-8

Business Equipment (DTE) Connections .............................................................................................................. 2-8

Communications Line Connections .......................................................................................................................2-8

DATA RATE ADAPTER CARD ...............................................................................................................................2-9

EIA-530 INTERFACE CARD ...................................................................................................................................2-9

3 — OPERATION

OVERVIEW...............................................................................................................................................................3-1

CONTROLS AND INDICATORS.............................................................................................................................3-1

RACKMOUNT SHELF .............................................................................................................................................3-1

4 — TESTS

OVERVIEW...............................................................................................................................................................4-1

LINE LOOPBACK TEST .........................................................................................................................................4-3

REMOTE LOOPBACK TEST...................................................................................................................................4-4

REMOTE TERMINAL TEST ...................................................................................................................................4-5

SELF-TESTS.............................................................................................................................................................4-6

END-TO-END SELF-TEST...................................................................................................................................... 4-8

i

TABLE OF CONTENTS (Cont.)


CSU LOOPBACK TEST ...........................................................................................................................................4-9

DSU LOOPBACK TEST ...........................................................................................................................................4-10

TECHNICAL ASSISTANCE PROCEDURE ...........................................................................................................4-11

TRAINING.................................................................................................................................................................4-12

APPENDIX A — TECHNICAL CHARACTERISTICS

APPENDIX B — BUSINESS EQUIPMENT (DTE) INTERFACE SIGNALS (EIA/TIA-232-E)

APPENDIX C — BUSINESS EQUIPMENT (DTE) INTERFACE SIGNALS (CCITT V.35)

APPENDIX D — BUSINESS EQUIPMENT (DTE) INTERFACE SIGNALS (EIA-530)

APPENDIX E — GLOSSARY

INDEX

LIST OF ILLUSTRATIONS

Section &Figure Page

2 — INSTALLATION

2-1 OPTION LOCATION..................................................................................................................................2-3

2-2 STANDALONE COVER REMOVAL PROCEDURE ................................................................................2-4

2-3 STANDALONE ENCLOSURE REAR PANEL CONNECTIONS............................................................2-10

2-4 DATACOMM/UNIVERSAL SYSTEM SHELF REAR PANEL CONNECTIONS...................................2-11

2-5 DATA RATE ADAPTER CARD INSTALLATION....................................................................................2-12

2-6 EIA-530 INTERFACE CARD INSTALLATION .......................................................................................2-13

3 — OPERATION

3-1 FRONT PANEL PUSH BUTTONS ...........................................................................................................3-1

3-2 FRONT PANEL INDICATORS AND DISPLAY (2 SHEETS) .................................................................3-2

4 — TESTS

4-1 FAULT-ISOLATION SEQUENCE ............................................................................................................4-2

4-2 LINE LOOPBACK TEST ...........................................................................................................................4-3

ii

LIST OF ILLUSTRATIONS (Cont.)


4-3 REMOTE LOOPBACK TEST .................................................................................................................... 4-4

4-4 REMOTE TERMINAL TEST.....................................................................................................................4-5

4-5 LINE LOOPBACK SELF-TEST ................................................................................................................ 4-6

4-6 REMOTE LOOPBACK SELF-TEST ......................................................................................................... 4-7

4-7 END-TO-END SELF-TEST .......................................................................................................................4-8

4-8 CSU LOOPBACK TEST.............................................................................................................................4-9

4-9 DSU LOOPBACK TEST.............................................................................................................................4-10

LIST OF TABLES

Section &Table Page

1 — INTRODUCTION

1-1 EQUIPMENT LIST .................................................................................................................................... 1-3

2 — INSTALLATION

2-1 OPTION APPLICATION NOTES (3 SHEETS)........................................................................................ 2-5

4 — TESTS

4-1 DIAGNOSTIC TEST PRIORITIES ........................................................................................................... 4-1

iii

SECTION 1

INTRODUCTION

DataComm500F/AXR

FEATURES

• DSU/CSU for direct connection to the DATAPHONE1 Digital Service.• Supports Standard DDS and generic digital service applications.• Provides extended range performance at all rates.• Can automatically detect line rate, or you can set it manually.• Operates at 64 kbps for “Clear Channel” service.• Operates in both point-to-point and multipoint configurations.• Provides a powerful Remote Loopback (RL) test for enhanced diagnos-

tic capabilities. Along with this standard General DataComm RL, italso provides V.54 and PN 127 type Remote Loopbacks.

• Optional plug-in Data Rate Adapter Card or EIA-530 Interface Card.

DESCRIPTION The DataComm 500F/AXR is a multirate Data Service Unit (DSU) thatincludes an on-board Channel Service Unit (CSU) for direct connection toDATAPHONE Digital Service (DDS).

The DataComm 500F/AXR is an autorate extended range DSU that pro-vides transmission and reception of serial binary data over the 4-wiremetallic circuits used in the DDS. It operates synchronously at data ratesof 2.4, 4.8, 9.6, 19.2, 56 and 64 kbps, or asynchronously at 1.2, 1.8, 2.4, 4.8,9.6 and 19.2 kbps.

The DataComm 500F/AXR normally derives timing from the DDS net-work (network or slave mode) or you can option it for internal (DSU) orexternal (DTE) clocking. The business equipment (DTE) interface con-forms to EIA/TIA-232-E or CCITT V.35, or optionally to EIA-530.

The DataComm 500F/AXR is available in standalone and rackmountmodels. The rackmount models feature GDC’s unique DataComm orUniversal System Shelf packaging concepts that allow a variety of datacommunications products, including up to 16 DSUs, to be mounted in thesame high-density shelf.

Table 1-1 lists the part numbers for the DataComm 500F/AXR’s standardand optional equipment. Appendix A describes the DataComm500F/AXR’s technical characteristics.

DIAGNOSTICS The DataComm 500F/AXR incorporates built-in diagnostic circuits to al-low quick and thorough performance tests for checking DSU operation.You can perform the Line Loopback (LL) and Remote Loopback (RL) testsindividually or in conjunction with the DSU's Self-Test (ST) feature, us-ing front panel push buttons. You can also control Analog Loopback (AL)and RL from the DTE interface. The Self-Test feature uses 511- or 2047-bittest pattern generator and error detector circuits. It also supports the fol-lowing telco Serving Test Center (STC) diagnostics: CSU Loopback

1 Registered Service Mark of AT&T Co.

1-1

INTRODUCTION

(current reversal), DSU Loopback (alternating pattern), and DSULatching Loopback at 64 kbps.

The DataComm 500F/AXR includes a Circuit Assurance option that turnsOFF the Clear to Send (CTS) lead during reception of an Out-of-Service(OOS) code from the network, or during the idle state. It also includes aSystem Status Option that turns OFF the Data Set Ready (DSR) lead dur-ing reception of an OOS code or during a No Signal (NS) condition.

SERVICE ANDTRAINING

Refer to Section 4 for information on service and training available fromGDC.

1-2

INTRODUCTION

TABLE 1-1. EQUIPMENT LIST

Description GDC Part No.DataComm 500F/AXR DSU, Standalone, 117 V ac 048A062-001DataComm 500F/AXR/530 DSU, Standalone, 117 V ac 048A062-011DataComm 500F/AXR/DRA DSU, Standalone, 117 V ac 048A062-021DataComm 500F/AXR DSU, Rackmount 048P062-001DataComm 500F/AXR/530 DSU, Rackmount 048M062-001DataComm 500F/AXR/DRA DSU, Rackmount 048M062-002

DataComm EnclosuresDataComm Enclosure DE-17A, 117 V ac 010B070-011Cover 010D500-003DataComm Shelf, DS-1, 117 V ac 010B015-001DataComm Shelf, DS-5R, –48 V dc redundant power supplies 010M011-001DataComm Shelf, DS-5NR, –48 V dc non-redundant power supply 010M011-002DataComm Shelf, DS-6R, –48 V dc redundant power supplies, NEBS-compliant dimensions 010M047-001DataComm Shelf, DS-6NR, –48 V dc non-redundant power supply, NEBS-compliant dimensions 010M047-002Universal System Shelf USS-1-D, 117 V ac, Domestic 010B080-001Universal System Shelf USS-1-DC/NR, –48 V dc non-redundant power supply 010M040-001Universal System Shelf USS-1-DC/R, –48 V dc redundant power supplies 010M040-002

Optional EquipmentData Rate Adapter Card 058P128-002EIA-530 Interface Card 048P042-001Crossover Adapter for DDS/Private Line Use 209-038-001VF Cable Assembly, 4-wire, 20 Feet 023H101-020Cable Assembly, 8 x 28, Modular-to-Modular 830-028-807Cable Assembly, Modular-to-Lugs 024H122-XXXV.35 Male-to-Male, Straight Through Cable 027H516-XXX*DB25 Male/V.35 Female Adapter Cable 027H560-001EIA-530/442 (25-pin male) to EIA-422/449 (37-pin female) Adapter Cable Assembly 027H501-001EIA/TIA-232-E Male-to-Male, Straight Through Cable 028H502-XXX*EIA/TIA-232-E Male-to-Female, Straight Through Cable (Shielded) 028H506-XXX*

Applicable PublicationInstallation of DataComm/NMS DSU Data Rate Adapter Card (GDC Part No. 058P128-002) 048R162-A1

* XXX = Cable length in feet

1-3

SECTION 2

INSTALLATION

OVERVIEW This section describes the installation of the DataComm 500F/AXR, in-cluding option selection.

UNPACKING ANDHANDLING

Inspect the DataComm 500F/AXR. If it is damaged, notify the shipperimmediately. Do not discard the box and packing material: their use fa-cilitates reshipping the unit, if necessary.

PREOPERATIONALCHECK

Upon power-up, the DSU lights all of its LEDs, displays its firmwarechecksum for five seconds, and then performs an Analog Loopback Self-Test. It displays the result of this test as either “PASS” or “FAIL.” If theDSU fails the power-up self-test, contact DataComm Service Corporation(refer to Section 4).

Before connecting the DSU to the communications line or DTE, you cangive it a further preoperational check by performing a Line LoopbackSelf-Test (refer to Section 4) to verify operation.

If the DSU passes the test, but subsequently fails to perform data commu-nications, it is probably not at fault. There is either an error in option se-lection or installation, or a faulty communications line or remote instal-lation.

Checking OptionSelection

Verify that option selection is the same as illustrated in Figure 2-1: all op-tion switches and jumpers (except X2) are in the left (OFF) position.

Checking theInstallation and

Line

Recheck the cable and line connections and, if necessary, perform thetests in Section 4 to isolate the problem. Verify that the remote DSU is acompatible type (e.g., a DSU operating at the same data rate). Also verifythat the DDS network is operating at the correct rate.

If the DSU does not check out properly, replace it with a spare and repeatthe test. Do not attempt to repair the DSU. For assistance, contactDataComm Service Corporation (refer to Section 4).

Transposed Lines If the transmit and receive lines are transposed (crossed), the TM/ALMLED flashes and the message “LinE” appears. Use of the wrong cable ormis-wiring of the telephone company-provided network interface maycause this problem and must be corrected.

Changes in ServiceRate

If the telco has changed the rate, either force the DSU to Auto-Rate by en-gaging front panel push buttons LL and RL simultaneously for at leastfive seconds or select the new rate with option switch S8.

NOTE

With Auto-Rate enabled, the DSU continually attempts todetermine the line type and rate on power-up or when theline signal was absent for longer than 10 seconds and recov-

2-1

INSTALLATION

ered. The DSU requires a full Auto-Rate cycle to accuratelydetermine the line type and rate.

INSTALLATIONPROCEDURES

The DSU plug-in module may be installed in a standalone DataCommEnclosure or rackmounted in a DataComm or Universal System Shelf(USS). Either installation should be located in a ventilated area where theambient temperature does not exceed 122°F (50°C). Do not install the unitdirectly above equipment that generates a large amount of heat (such aspower supplies).

StandaloneInstallation

If it is necessary to remove the component cards from the standalonebase, disconnect the power supply connector from J1, which is mounted atthe rear center of the base card. When reinstalling the component cardsto the base, reinstall the connector at J1. Refer to Figures 2-1 and 2-2.

RackmountInstallation

The DataComm 500F/AXR may be mounted in a DataComm Shelf (DS-1,DS-5 or DS-6) which may support as many as 16 DSUs. The DSU may beinstalled in any unused slot in the shelf. To install the unit in the shelf,proceed as follows:

1. Position the plug-in module in the top and bottom slot guides with theGDC logo on top, and carefully slide the assembly into the slot until itstops at the rear connectors.

2. Push the front panel with both hands until the assembly seats in therear connectors.

The Universal System Shelf (USS) may also be used and accommodates16 DSUs. The USS uses harness cards and backplanes configured to oc-cupy one slot in the shelf for each DSU.

Each backplane assembly is keyed by a tab located at the bottom of theharness card. This tab fits into a slot that is part of the shelf and preventsthe backplanes from being inserted incorrectly in the shelf.

To install the DSU into the USS shelf, proceed as follows:

1. Loosen the backplane screws and install the plug-in module fromthe front of the shelf by sliding it into the card guides. Seat firmlyinto the mating connectors on the backplane using both hands.

2. Tighten the backplane screws. This assures perfect alignment ofthe plug-in modules in the card guides and the mating connectors onthe backplane and allows for easy removal of the plug-in modules.Plug in the four-pin cable harness on the backplane adapter to theshelf power connector located directly above the backplane adapter.

OPTIONSELECTION

The field-selectable options adapt the DataComm 500F/AXR to a variety ofconfigurations. You select these options by positioning DIP switches onthe DSU base card.

Figure 2-1 shows the location of each option switch, and Table 2-1 de-scribes the function and application of each option.

2-2

INSTALLATION

J1

FL1

F1

J3

F2

X2OPEN SEP

COM

S8

1.2K1.8K2.4K4.8K9.6K19.2K56K64K

DATA RATE

1 2 3 4 5 6 7 8

O N

S12

FRONT PANEL INHIBCIRCUIT ASSURANCESYSTEM STATUSWIRELINE (LDM)

1 2 3 4

O N

S9

INTERNAL TIMINGEXTERNAL TIMINGEXTERN BUFF CLKPERMANENT RTSANTI-STREAMING64K SCRAMBLER2047 ST PATTERNEXTEND CTS DELAY

1 2 3 4 5 6 7 8

O N

S11

ASYNCHRONOUSWORD LENGTH 0WORD LENGTH 12% OVERSPEEDRL INHIBITV.54 RLP127 RLRL TIMEOUT

1 2 3 4 5 6 7 8

O N

S7

ALERLETME

1 2 3 4

O N

V.35 RS232

X1

XA1P3

XA1P2

J2

XA

1P1

S7-4 is not used

NOTE

For asynchronous applications where clock signals are not desirable, uncovering pins 8 and 24 (EIA pin 15) and pins 9 and 25 (EIA 17) at connector XA1P3 removes the timing signals from EIA pins 15 and 17.

25 172432

916

Shift jumpers onepin to the sides

XA1P3

8 1

FIGURE 2-1. OPTION LOCATION

2-3

INSTALLATION

2

CAUTION: Disconnect power cable and communications line connections before removing cover.

With front of unit facing left, turn screw on rear panel to release cover.

Lift right end of cover upward.(For dual-card products, spread the sides of the cover to clear the upper card.)

Slide cover to left with an upward motion.

When reinstalling cover, top edge of rear panel must sit between the two ridges on underside of cover.

3

1

1

2

3

FIGURE 2-2. STANDALONE COVER REMOVAL PROCEDURE

2-4

INSTALLATION

TABLE 2-1. OPTION APPLICATION NOTES(JUMPERS X1 AND X2, AND SWITCHES S7 AND S8)

OptionSwitch (S) orJumper (X) Description

DTE Interface Type X1(V.35/RS232)

Jumper positions select EIA/TIA-232-E or CCITT V.35 DTE in-terface. Factory set to V.35 position. If the optional Data RateAdapter Card is installed, X1 must be in the RS232 position. Ifthe optional EIA-530 Interface Card is installed in the activeposition, the interface type is EIA-530 regardless of thesetting of X1.

Grounds X2(OPEN/COM/SEP)

This option provides separation or connection of protectiveand signal grounds. Separation of grounds (by 100 ohms oropen) is selected with consideration given to power line noise,differences in ground potential, DTE manufacturer'srecommendations, and safety requirements. Direct connec-tion reduces the effects of longitudinal power line noise.

DTE Control of AnalogLoopback Test

S7-1(ALE)

The DSU may be optioned to permit the DTE to control theAnalog Loopback (AL) test mode via pin-18 of the EIA/TIA-232-E interface or pin J of the V.35 interface.

DTE Control of RemoteLoopback Test

S7-2(RLE)

The DSU may be optioned to permit the DTE to control theRemote Loopback (RL) test mode via pin 21 of the EIA/TIA-232-E interface or pin BB of the V.35 interface.

DSU Control of Test ModeIndicator

S7-3(TME)

The DSU may be optioned to permit the DSU to control theTest Mode (TM) indicator (pin 25 of the EIA/TIA-232-E inter-face or pin K of the V.35 interface).

n/a S7-4 not used

Data Rate Selection

Manual

Auto-Rate

S8-1 through S8-8(1.2K through 64K)

(all OFF)

Set one switch only to the desired data rate as follows:

Data Rate Switch ON Async Sync1.2 kbps S8-1 √1.8 kbps S8-2 √2.4 kbps S8-3 √ √4.8 kbps S8-4 √ √9.6 kbps S8-5 √ √19.2 kbps S8-6 √ √56 kbps S8-7 √64 kbps S8-8 √

The DSU has the ability to configure itself to operate with theinstalled service (DDS) and at the proper data rate, automati-cally. This will occur with no switch or more than one switchselected on S8-1 through S8-8. (Auto-Rate is not applicablefor 1.2 kbps or 1.8 kbps. For LDM applications using Auto-Rate, do not select network timing for both ends: Select eitherinternal or external timing for one end, and network timing forthe other end.)

2-5

INSTALLATION

TABLE 2-1. OPTION APPLICATION NOTES (CONT.)(SWITCH S9)


Timing Source Selection(LDM Applications)

S9-1(INTERNAL TIMING)

S9-2(EXTERNAL TIMING)

With internal timing, the transmit timing is derived internal tothe DSU. With external timing, the transmit timing is providedby the DTE. If neither external nor internal timing is selected,the DSU defaults to network (Slave) timing, and the transmittiming is derived from the network.

Timing Source S9-1 S9-2 ApplicationNetwork (slave) OFF OFF DDS

Internal ON OFF LDMExternal OFF ON LDM

External Transmit BufferClock

S9-3(EXTERN BUFF CLK)

When ON, and when the timing source is Internal or Slave, theinput clock to the buffer is the DTE clock (external). WhenOFF, the input clock to the buffer is the DSU transmit timing.When the timing source is External, the buffer clock is alwaysthe DTE clock.

Permanent RTS S9-4(PERMANENT RTS)

When ON, both RTS and CTS remain ON regardless of thestate of the attached DTE (the transmitter is ON regardless ofthe status of the RTS interface lead) When OFF, the RTS-to-CTS delay is determined by S9-8.

Anti-Streaming S9-5(ANTI-STREAMING)

When ON, the DSU transmitter is forced OFF (idle) if the DTERTS lead remains ON for more than 20 seconds. Anti-Streaming releases when the RTS interface lead turns OFFand remains OFF for 100 ms. When a streaming condition isdetected, the TM/ALM LED will blink, DTE pin 25 (TM) willtoggle and “AS” will be displayed. When OFF, Anti-Streamingis disabled.

64K Scrambler(Available when operating at64 kbps only)

S9-6(64K SCRAMBLER)

When ON, a scrambler and descrambler are inserted into thedata path. When OFF, they are bypassed.

2047 Self-Test Pattern S9-7(2047 ST PATTERN)

When ON, a 2047-bit test pattern is used during Self-Test.When OFF, a 511-bit test pattern is used.

Extended CTS Delay S9-8(EXTEND CTS DELAY)

RTS-to-CTS delay. Normal (3-byte delay) is OFF; extended(45 ms delay) is ON. Use extended delay in an applicationsuch as an analog modem tail circuit on the far end where datamay be lost if CTS is asserted too soon. (This option isignored when S9-4 is OFF.)

2-6

INSTALLATION

TABLE 2-1. OPTION APPLICATION NOTES (CONT.)(SWITCHES S11 AND S12)


Asynchronous S11-1(ASYNCHRONOUS)

When ON, forces the DSU to perform an asynchronous tosynchronous conversion, allowing customer equipment toasynchronously transmit on the data path. When OFF, syn-chronous mode is selected.

Word Size Selection S11-2(WORD LENGTH 0)

S11-3(WORD LENGTH 1)

These two switches select the asynchronous word size(number of bits per character). The option is ignored in syn-chronous mode or 56 and 64 kbps operation.

Word Size S11-2 S11-311 ON ON10 OFF OFF09 OFF ON08 ON OFF

Extended Overspeed S11-4(2% OVERSPEED)

When ON and in asynchronous operation, up to 2.3% datarate overspeed can be accommodated. When OFF, a defaultof 1% overspeed is selected.

Remote Loopback Inhibit S11-5(RL INHIBIT)

ON = DSU does not accept Remote Loopback commandfrom remote DSU or Latching Loopback commandfrom STC.

OFF = DSU accepts both Remote Loopback and LatchingLoopback commands.

Remote Loopback Methods S11-6(V.54 RL)

S11-7(P127 RL)

These two switches allow selection of GDC, CCITT V.54 or PN127 Remote Digital Loopback methods. The local and remoteDSUs must have the same RL method selected for properoperation. (GDC RL not available at 64 kbps.)

RL Method S11-6 S11-7Remote Loops Inhibited OFF OFFPN 127 Remote Loop Enabled OFF ONV.54 Remote Loop Enabled ON OFFGDC Remote Loop Enabled ON ON

Remote Loopback Timeout S11-8(RL TIMEOUT)

When ON, selects 10-minute automatic RL timeout. WhenOFF, no timeout is selected (RL must be terminated manu-ally).

Front Panel Inhibit S12-1(FRONT PANEL INHIBIT)

When ON, inhibits front panel control of all diagnostics (LL,ST, RL and RT), including the Force Auto-Rate feature. WhenOFF, front panel control of all diagnostics is supported.

Circuit Assurance S12-2(CIRCUIT ASSURANCE)

When ON, forces OFF Clear-To-Send (CTS) when the DSUreceives Idle or Out-of-Service codes. When OFF, CTS op-erates normally.

System Status S12-3(SYSTEM STATUS)

When ON, forces OFF Data Set Ready (DSR) during thereception of the Out-of-Service codes or during periods of nosignal reception. When OFF, DSR operates normally.

Remote Loopback Inhibit(LDM Applications)

S12-4(WIRELINE (LDM))

When ON, allows RDL to be initiated from the slave-timed unitwhile in LDM mode. When OFF, RDL should not be initiatedfrom the slave-timed unit while in LDM mode.

2-7

INSTALLATION

ELECTRICALCONNECTIONS

The following paragraphs describe the power line, business equipment(DTE), and communications line connections to the DataComm500F/AXR. Figure 2-3 illustrates the standalone enclosure rear panel andFigure 2-4 illustrates the rackmount shelf rear panel.

StandaloneEnclosure

The unit is equipped with a captive ac power cord terminated in a moldedthree-prong plug. Connect the cord to a polarized outlet providing the re-quired ac power. The outlet should not be under switch control. The unitshould be powered by the same ac source as the equipment interfaced withthe unit, to prevent large circulating currents caused by differences inground potential. If it is not possible to determine whether the equipmentis powered by the same ac source, it should be verified that a potential dif-ference of less than 0.25 V rms exists between the grounding circuits ofthe respective power outlets.

NOTE

This unit incorporates a fusible link, FL1 (shown in Figure2-1), which may be opened if the ground potential exceeds0.25 V rms between the unit and peripheral equipment. Donot apply power to the unit until all connections to periph-eral equipment have been made. If a fusible link is openedin a unit, return it to the factory for repair.

Rackmount Shelf The DSU obtains power directly from the shelf when properly installed asinstructed under Rackmount Installation.

BusinessEquipment (DTE)

Connections

The DataComm 500F/AXR supports three business equipment (DTE) in-terfaces: EIA/TIA-232-E, CCITT V.35 and EIA-530. The EIA/TIA-232-Eand V.35 interface hardware resides on the DataComm 500F/AXR basecard and the interface type is selected with jumper X1. The EIA-530 inter-face requires the optional EIA-530 Interface Card, described below.

Business equipment connections to the standalone DSU are made via the25-pin connector labeled RS232/530 or the 34-pin V.35 connector labeledV.35. Connections to the rackmount DSU are made via the 25-pin connec-tor labeled Business Equip.

Appendixes B through D describe the signals exchanged through each ofthe business equipment interfaces.

CommunicationsLine Connections

When the DSU is installed in the standalone enclosure, the DSU is con-nected to the communications line using the modular jack at the rearpanel.

NOTE

The transmit pair is on pins 1 and 2, and the receive pair ison pins 7 and 8. Pin 1 is on the left and pin 8 is on the right,when the jack is viewed from the rear.

If the DSU is rackmounted in the DataComm Shelf DS-l, the four wirecommunications line is connected to the top four screws of the terminalblock mounted on the shelf's rear panel. If the unit is mounted in theUniversal System Shelf, the plastic cover attached at the rear of the back-plane must first be removed to expose the VF terminal blocks. These

2-8

INSTALLATION

blocks accommodate wires that do not have terminal lugs. Remove thelugs and a portion of the insulation on the existing cable and insert thewires into the block by first unscrewing the captive screw for that portionof the terminal. Replace the plastic cover.

In either case, before making the connection, verify that the terminalblock corresponds to the shelf receptacle in which the DSU plug-in moduleis installed.

DATA RATEADAPTER CARD

An optional Data Rate Adapter Card is available as a factory installed op-tion, or as a field upgrade kit. The Data Rate Adapter Card (GDC PartNo. 058P128-002) plugs into the DataComm 500F/AXR base card, as illus-trated in Figure 2-5.

The Data Rate Adapter Card adapts synchronous and asynchronous DTEdata transmission speeds of 19.2 kbps and slower to an aggregate linespeed of 56 or 64 kbps. Rate adaptation is provided for point-to-point andmultipoint applications.

For complete operating and installation instructions applicable to theData Rate Adapter Card, refer to Publication No. 048R162-A1.

NOTE

You cannot install the Data Rate Adapter Card and the EIA-530 Interface Card at the same time.

EIA-530INTERFACE CARD

The optional EIA-530 Interface Card provides an EIA-530 interface for theDTE . It is available factory installed, or as a field upgrade kit. The EIA-530 Interface Card plugs into the base card in one of two ways, as illus-trated in Figure 2-6. In the active position, the EIA-530 Interface Card pro-vides the EIA-530 interface, regardless of the interface selected withjumper X1. In the bypass position, the EIA-530 Interface Card acts as ajumper for XA1P2 and XA1P3, making the base card interface active.(You can also remove the EIA-530 Interface Card and place jumpers onXA1P2 and XA1P3 to make the base card interface active.)

To install the EIA-530 Interface Card:

1. Turn OFF the unit.2. Remove the cover from the standalone unit to gain access to the plug-

in module, or remove the plug-in module from the rackmount shelf.3. Remove the jumpers installed on connectors XA1P2 and XA1P3.4. Plug the EIA-530 Interface Card into the base card in either the active

or the bypass position.5. Reinstall the cover on the standalone unit or insert the plug-in mod-

ule into the shelf.6. Turn ON the unit.

NOTE

a. When the optional EIA-530 Interface Card is installed inthe active position, DTE control of Remote Terminal Testand Self-Test is not supported.

b. You cannot install the EIA-530 Interface Card and theData Rate Adapter Card at the same time.

2-9

INSTALLATION

Business equipment connector for EIA/TIA-232-E or EIA-530 interface.For EIA/TIA-232-E, use cable P/N 028H502-XXX (male-to-male) or 028H506-XXX (male-to-female).For EIA-530, install the EIA-530 Interface Card and use adapter cable P/N 027H501-001 (25-pin male to 37-pin female).

Communications line connector. Use cable P/N 024H122-XXX (modular-to-lugs) 830-028-807 (modular-to-modular).

General DataComm, Inc.Middlebury, Ct.

Auxiliary 1

DataComm Enclosure MODEL DE-17

Serial No.

NFPA TYPE II117V 60Hz0.2 Amps

RS232/530

ACPWR

V.35

LINE

Business equipment connector for CCITT V.35 interface. Use cable P/N 027H516-XXX (male-to-male).

FIGURE 2-3. STANDALONE ENCLOSURE REAR PANEL CONNECTIONS

2-10

INSTALLATION

Private Line to DDS Adapter

RedGreenYellowBlack

DS-1DataComm Shelf

rear panel

MODEL No. DC-1/BP

USS-1Universal System Shelf

rear panel

BUSINESS

E QUIP

TELEPHONE

T/TR/RPC/DTPR/DRMIC/TEC 5MIC/TEC 6

Communications line connector. Use Private Line to DDS Adapter (P/N 209-038-001) and cable 024H122-XXX (modular-to-lugs) or 830-028-807 (modular-to-modular).

Alternate communications line connector. Use cable P/N 023H101-020.

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

R1

T1

TEK 5

not used

not used

TEK 6

T

R

not used

not used

TEK 5

R1

T1

TEK 6

T

R

Plug P1To shelf modular connector.

Jack J1To DDS line.

2-wire transmit/receive4-wire transmit

4-wire receive

Business equipment connector for all interface types.For EIA/TIA-232-E, use cable P/N 028H502-XXX (male-to-male) or 028H506-XXX (male-to-female).For CCITT V.35, use adapter cable P/N 027H560-001 (male-to-female).For EIA- 530, install the EIA-530 Interface Card and use adapter cable P/N 027H501-001 (25-pin male to 37-pin female).

FIGURE 2-4. DataComm/UNIVERSAL SYSTEM SHELF REAR PANEL CONNECTIONS

2-11

INSTALLATION

V.35 RS232

X1

NOTE: Be sure that jumper X1 is in the RS232 position when using the Data Rate Adapter Card.

J2

XA

1P1

XA1P2

XA1P3

J2

J3

Data Rate Adapter Card(solder side)

J1

Connector mating:J2 to XA1P2J3 to XA1P3J1 to XA1P1

FIGURE 2-5. DATA RATE ADAPTER CARD INSTALLATION

2-12

INSTALLATION

V.35 RS232

X1

NOTE: When the EIA-530 Interface Card is installed in the bypass position, be sure to select the correct interface type with jumper X1.

J2

J3

EIA-530 Interface Card(solder side)

EIA-530 Interface Cardin the active position

J1

Connector mating:J2 to XA1P2J3 to XA1P3J1 to XA1P1

J4

J5

EIA-530 Interface Cardin the bypass position

Connector mating:J4 to XA1P2J5 to XA1P3

EIA-530 Interface Card(solder side)

J2

XA

1P1

XA1P2

XA1P3

Location of theEIA-530 Interface Card

FIGURE 2-6. EIA-530 INTERFACE CARD INSTALLATION

2-13

SECTION 3

OPERATION

OVERVIEW All operations of the DataComm 500F/AXR are controlled automaticallyafter it is properly installed. It has no operating instructions (except fortest procedures given in Section 4, Tests). This section describes the con-trols and indicators of the unit that the operator may use to check the op-eration of the DSU.

CONTROLS ANDINDICATORS

Figures 3-1 and 3-2 illustrate the DSU's front panel and explain the func-tion of each control and indicator.

RACKMOUNTSHELF

Rackmount shelf front panel controls, indicators, and fuses are describedin the manual supplied with the shelf. Refer to it if you have a rackmountshelf. The shelf's rear panel and connectors are illustrated in Section 2.

ON500F/AXR TM / ALMCOLL ST RL

RS CSRDSDRT

Engaging this push button causes the local DSU's test pattern generator to generate and check a selectable test pattern. If the DSU detects errors, it displays the percentage of error-free-seconds ("nn.nE"). When the DSU is in a self-test mode, and you disengage then engage this push button (within approximately 2 seconds), the percentage of error-free seconds counter is cleared (the test pattern generator is not affected).

Engaging this push button initiates Remote Digital Loopback (i.e., places the remote DSU in Remote Terminal Loopback).

Engaging this push button places the local DSU in Line Loopback.

With Auto-Rate enabled, engaging LL and RL simultaneously for at least 5 seconds forces the DSU to Auto-Rate. Before performing Auto-Rate, the DSU alternately displays "Auto" and the current rate, and you can cancel Auto-Rate by disengaging the push buttons.

Engaging this push button places the local DSU in Remote Terminal Loopback.

FIGURE 3-1. FRONT PANEL PUSH BUTTONS

3-1

OPERATION


RS CSRDSDRT

ON when DSU has ac voltage and DSU power supply is 5 V dc.

ON when DTE is ready to send data. Also ON during self-test modes or when Permanent RTS option is enabled.

ON when DSU is ready to send data. OFF during self-test modes.

ON when DSU is receiving data. OFF during self-test modes.

ON when a space bit is present in send data.

ON when received data is a space.

ON when DSU is in test mode or flashes for an alarm state.

See Sheet 2 for a description of the display.

FIGURE 3-2. FRONT PANEL INDICATORS AND DISPLAY (Sheet 1 of 2)

3-2

OPERATION

Data rate is 1.2 kbps






Data rate is 56 kbps

Data rate is 64 kbps

Out of Service alarm (TM/ALM LED flashes)

Unit passed Power-up Self-Test

Unit failed Power-up Self-Test, Line Loopback with Self-Test, V.54 RL or GDC RL

Auto-Rate in progress; "Auto" and current rate alternate for 5 seconds preceding a forced Auto-Rate

DDS communication line crossed alarm (TM/ALM LED flashes)

Streaming DTE alarm (TM/ALM LED flashes)

DTE-initiated Analog Loopback

Line Loopback from front panel push button

Line Loopback from telco Serving Test Center (STC) current reversal

Remote Terminal test from STC codes

Remote Loopback from front panel push button

Remote Loop condition (initiated from other end)

Power-up Self-Test

Line Loopback with Self-Test from front panel push button

Remote Loopback with Self-Test from front panel push button

Percentage of error-free seconds during Self-Test mode (00.0E to 99.9E)

DTE-initiated Remote Loopback

No Signal alarm (TM/ALM LED flashes)

511 Self-Test pattern selected

2047 Self-Test pattern selected

PN 127 RL test selected

V.54 RL test selected

GDC RL test selected

Reset percentage of error-free seconds counter during Self-Test

When alternating with nn.nE, error-free seconds is being computed.When on steady, test is 100% error free.

18.2 hour test is finished



Alphanumeric characters 0 to 9, A to F, during Power-up Self-Test displays firmware checksum for 5 seconds

Remote Terminal Loopback from front panel push button

FIGURE 3-2. FRONT PANEL INDICATORS AND DISPLAY (Sheet 2 of 2)

3-3

SECTION 4

TESTS

OVERVIEW This section describes the tests that you can perform after installing theDataComm 500F/AXR or whenever you must check its operation. You canalso use these tests to isolate problems in the data communications system(refer to the fault-isolation sequence in Figure 4-1).

The SD and RD LEDs may appear to be ON or to flicker, depending onthe data rate at which you are testing the unit. When the DSU is operatingat the higher rates (above 9600 bps), the indicators may appear to besolidly ON; below that they may appear to flicker. The test descriptionsand front panel indicators shown in the illustrations assume that the unithas established its test and is operating at 9600 bps or below.

NOTE

a. Diagnostics may be controlled from the front panel pushbuttons, the DTE interfaces or from the telco’s ServingTest Center (STC), depending on the specific test.

b. You can option the DSU to permit the DTE to controlAnalog Loopback Test and Remote Loopback (refer toTable 2-1).

c. Table 4-1 describes the diagnostic test priorities.d. To force the DSU to Auto-Rate and determine the line

type and rate, engage front panel push buttons LL andRL simultaneously for at least five seconds. (Before per-forming Auto-Rate, the DSU displays “Auto” and youcan cancel Auto-Rate by releasing the push buttons.)When Auto-Rate is complete, the DSU displays the linerate. If it is not the expected rate, contact the telco.

TABLE 4-1. DIAGNOSTIC TEST PRIORITIES

Priority Test Means of Activation Display1 CSU Loopback STC (current reversal) CSU2 LL/LL-ST Front Panel LL/LL-S3 DSU Loopback STC (Codes) (if activated first, has priority over

LL/LL-ST)dSU

4 RT (Local) Front Panel rtLb5 RL/RL-ST Front Panel rL/rL-S6 AL DTE (if activated first, has priority over DSU

Loopback)d-AL

7 RL DTE d-rL8 ST Front Panel EFS9 RT (Remote) (from remote RL) LOOP

4-1

TESTS

START

Perform Line Loopback on local DSU

Perform Line Loopback Self-Test on local DSU

Perform Line Loopback Self-Test on remote DSU

Perform End-to-End Self-Test

Faulty local DSU or check optioning

Faulty communication line

Faulty remote DTE or remote DSU-DTE connection

Faulty local DTE or local DSU-DTE connection

PassorFail?

Pass Fail

PassorFail?

Pass Fail

PassorFail?

Pass FailFaulty remote DSU or check

optioning

PassorFail?

Pass Fail

FIGURE 4-1. FAULT-ISOLATION SEQUENCE

4-2

TESTS

LINE LOOPBACKTEST

Line Loopback (LL) checks the performance of the DSU and its associatedDTE. The DSU disconnects its line transmitter and receiver from thecommunications line, then connects them together, creating a circuitsimilar to an Analog Loopback circuit that loops signals from the trans-mitter through the receiver. It also connects the transmit and receivecommunications lines together, creating a circuit (the Line Loopback cir-cuit) that loops received signals back over the communications line to theremote DSU. Figure 4-2 illustrates LL.

While the local DSU is performing Line Loopback, the remote DSU cansend a Self-Test pattern to the local DSU, which loops the test pattern backto the remote DSU for verification. This test checks the performance of theremote DSU and the communications line. To perform this test, make ar-rangements with the remote site personnel before initiating LineLoopback locally.

NOTE

The Analog Loopback portion of this test can also be con-trolled via the DTE. Refer to the description of option switchS7-1 in Table 2-1.


RS CSRDSDRT

ANALOGLOOP

LINELOOP

1. Engage push button LL.

2. TM LED will be ON during test.

5. SD and RD will flicker an exact copy of test message.

3. "LL" will be displayed. 6. Disengage push button LL to end test.

4. Initiate a test message from the DTE. This may be done by typing a message on the DTE keyboard.

FIGURE 4-2. LINE LOOPBACK TEST

4-3

TESTS

REMOTELOOPBACK TEST

Remote Loopback checks the performance of the local and remote DSUs,the local DTE, and the communications line. When you initiate this test,the remote DSU enters the RT Loopback condition. The remote DSU dis-connects its DTE transmitter and receiver from the DTE interface, thenconnects them together, creating a circuit that loops the receiver's digitaloutput signals to the transmitter's input. Figure 4-3 illustrates RL.

NOTE

Remote Loopback can also be controlled via the local DTE.Refer to the description of option switch S7-2 in Table 2-1.


RS CSRDSDRT


RS CSRDSDRT

LOCALDSU

REMOTEDSU

1. Engage push button RL. This places the remote DSU in an RT Loopback condition.2. CO and TM will be ON during test.

3."rL" will be displayed when RL training sequence is completed.

7. SD and RD will flicker an exact copy of test message.

9. Disengage push button RL to end test.

6. Initiate a test message from the local end of the data communications circuit.

4. RS, CO and TM will be ON during test.

5. "LooP" will be displayed. 8. SD and RD will flicker an exact copy of test message.

FIGURE 4-3. REMOTE LOOPBACK TEST

4-4

TESTS

REMOTETERMINAL TEST

Remote Terminal (RT) test checks the performance of the local and re-mote DSUs, the remote DTE, and the communications line. When youinitiate this test, the local looping DSU disconnects its DTE transmitterand receiver from the DTE interface, then connects them together, creat-ing a circuit that loops the receiver's digital output signals to the trans-mitter's input. Figure 4-4 illustrates RT.

1. Engage push button RT at the looping (local) DSU.

3."rtLb" will be displayed. 5. SD and RD will flicker at the remote DSU.

7. Disengage push button RT at the local DSU to end test.

4. Initiate a test message at the remote DSU.

2. RS and TM will light at the local DSU.

6. An exact copy of the test message should be received at the remote DSU.


RS CSRDSDRT

FIGURE 4-4. REMOTE TERMINAL TEST

4-5

TESTS

SELF-TESTS The Self-Test function causes the DSU to generate a test pattern and mon-itor the received signal for errors in the received test pattern. Optionswitch S9-7 selects either a 511- or 2047-bit test pattern for the pattern gen-erator and error detector. Figures 4-5 through 4-7 illustrate Self-Test. If theDSU detects any errors, the front panel displays the percentage of error-free seconds. You can use Self-Test in place of DTE-generated test mes-sages for the Line Loopback and Remote Loopback tests.

Self-Test computes the percentage of error-free seconds for up to 18.2hours. At the end of this time, the DSU freezes the percentage of error-freeseconds display, although the Self-Test generator and checker continue tofunction. The maximum Self-Test time reached is indicated by lightingall of the decimal points.

During Self-Test, if you disengage the Self-Test push button and then en-gage it within two seconds, the DSU resets the percentage of error-freeseconds counter.


RS CSRDSDRT

LOCALDSU

1. Engage push button LL.

2. Engage push button ST.3. RS, CO and TM will be ON during test.

4 "LL-S" will be displayed if no errors are detected. *

5. SD and RD will flicker. 6. Disengage push buttons ST and LL to end test.

If an error is detected, the "FAIL" message will be displayed, the test will be terminated, and the DSU will resume its previous mode."LL-S" will be displayed as "L.L.-.S." when the maximum Self-Test time has been reached.

PATTERNGENERATOR

ERRORDETECTOR

TXLOGIC

RXLOGIC

LINELOOP

DSU

ANALOGLOOP SELF-TEST

*

FIGURE 4-5. LINE LOOPBACK SELF-TEST

4-6

TESTS


RS CSRDSDRT


RS CSRDSDRT

LOCALDSU

1. Engage push button RL. This places the remote DSU in an RT Loopback condition.

2. After "rL" appears on display, engage push button ST.


4. "rL-S" will be displayed if no errors are detected. *

5. SD and RD will flicker. 9. Disengage push buttons ST and RL to end test.


8. SD and RD will flicker. 7. "LooP" will be displayed.

REMOTEDSU

"nn.nE" will be alternately displayed with "rL-S" if errors are detected."nn.n" denotes percentage of error-free seconds."rL-S" will be displayed as "r.L.-.S." when the maximum Self-Test time has been reached.

*

FIGURE 4-6. REMOTE LOOPBACK SELF-TEST

4-7

TESTS

END-TO-END SELF-TEST

In addition to using the Self-Test function in conjunction with other testfeatures, you can Self-Test independently. In End-to-End Self-Test, the lo-cal and remote DSUs exchange Self-Test patterns to check the perfor-mance of the communications line and the local and remote DSUs (notincluding the DSUs' DTE interfaces). Option switch S9-7 selects either a511- or 2047-bit test pattern for the pattern generator and error detector.Figure 4-7 illustrates End-to-End Self-Test.


RS CSRDSDRT

LOCAL AND REMOTEDSUs

1. Engage push button ST on local DSU. Direct attendant to engage push button ST on remote DSU.

2. SD and RD will flicker.

3. "EFS" will be displayed if no errors are detected. *

4. Disengage push button ST to end test.

"nn.nE" will be alternately displayed with "EFS" if errors are detected." nn.n" denotes percentage of error-free seconds."EFS" will be displayed as "E.S.F." when the maximum Self-Test time has been reached.

5. When push button ST is disengaged then engaged again (within about 2 seconds), the percentage of error-free seconds counter is cleared (the test pattern generator is not affected).

RS, CO and TM will be ON during test.

*

FIGURE 4-7. END-TO-END SELF-TEST

4-8

TESTS

CSU LOOPBACKTEST

The CSU Loopback test is controlled by the STC, which reverses the polar-ity of the sealing current. When the DSU detects the reversed current, itdisconnects its line transmitter and receiver from the communicationsline and connects them together. It also connects the transmit and receivecommunications lines together, creating a circuit (the Line Loopback cir-cuit) that loops received signals back over the communications line to theSTC. Figure 4-8 illustrates CSU Loopback.

When it is necessary to isolate a problem, contact the STC and ask themto initiate the CSU Loopback test. Use the test results in conjunction withthe fault-isolation sequence (Figure 4-1) to pinpoint a problem, if any.

While the unit is in CSU Loopback, you can send a test message from thelocal DTE through the local DSU, which loops the message back to theDTE for verification. This test checks the performance of the local DSU,DTE and DSU-DTE interconnections.


RS CSRDSDRT

ANALOG LOOPLINE

LOOP

SD

RD

2. TM will be ON during test.

3. "CSU" will be displayed. 4. SD and RD will flicker an exact copy of test message.

1. Contact the STC and ask them to initiate the CSU Loopback test.

5. Coordinate with the STC to end test.

FIGURE 4-8. CSU LOOPBACK TEST

4-9

TESTS

DSU LOOPBACKTEST

The DSU Loopback test is controlled by the STC, which sends networkcodes. When the DSU detects the codes, it disconnects its line transmitterand receiver from the communications line, then connects them together,creating a circuit that loops the receiver's digital output signals to thetransmitter's input. Figure 4-9 illustrates DSU Loopback.

When it is necessary to isolate a problem, contact the STC and ask themto initiate the DSU Loopback test. Use the test results in conjunction withthe fault-isolation sequence (Figure 4-1) to pinpoint a problem.

ON500F/AXR TM / ALMCOLL S

TRL

RS CSRDSDRT

2. RS and TM will be ON during test.

4. "dSU" will be displayed. 3. SD and RD will flicker.

DTEINTER-FACE

TX LOGIC

RXLOGIC

ANALOGRECEIVER

TXDRIVER

DSU

S T C

1. Contact the STC and ask them to initiate the DSU Loopback test.

5. Coordinate with the STC to end test.

FIGURE 4-9. DSU LOOPBACK TEST

4-10

TESTS

TECHNICALASSISTANCEPROCEDURE

For technical assistance, customers should call DataComm ServiceCorporation at 203-598-7526.

In Canada:

General DataComm (Canada) Ltd.Service and Repair Facility1790 Beaulac StreetSt. Laurent, Montreal, Quebec H4R 1W8Telephone: 1-514-336-5454TWX: 610-421-3221Telex: 05824085

In the United Kingdom, contact the GDC area manager at:

General DataComm (U.K.) Ltd.Molly Millars CloseMolly Millars LaneWokingham, BerkshireEngland RG11 2QFTelephone: 011-44-734-774-868Telex: 851 847298Fax: 011-44-734-774-871

In Europe/Africa/Middle East:

General DataComm3 Batiment SaturneParc Club ArianeRue Helene Boucher78284 Guyancourt Cedex, FranceTel: 011-33-1-30570200Fax: 011-33-1-30443794

In the Pacific:

General DataComm Pty.Suite 404275 Alfred Street NorthNorth Sydney, NSW 2060, AustraliaTel: 011-61-2-956-5099Fax: 011-61-2-956-5083

In Asia:

General DataComm401 Centry Square1-13 D'Aguilar StreetCentral, Hong KongTel: 011-852-5265511Telex: 780-80579Fax: 011-852-5259944

4-11

TESTS

In Latin America:

General DataComm, International1579 Straits TurnpikeP.O. Box 1299Middlebury, Connecticut 06762-1299Telephone: 203-574-1118Telex: 7400905Fax: 203-758-9518

To return a unit for repair, if so authorized by GDC, use the return tagand address the package:

Product Repair DepartmentGeneral DataComm, Inc.1579 Straits TurnpikeP.O. Box 1299Middlebury, Connecticut 06762-1299

Lease and Maintenance contract customers may call DataComm ServiceCorporation toll-free at 1-800-243-1030, 24 hours a day, 7 days a week fortrouble reporting or installation scheduling. (Installations are normallyscheduled between 8 a.m. and 5 p.m.)

TRAINING Hands-on training courses are available from DataComm ServiceCorporation's Educational Services in the USA and in the UK. Courses of-fered range from basic data communications, modems and multiplexers,to complex network systems, and are given at GDC’s Connecticut facilityor at a customer’s location.

For information call:

USA (203) 574-1118, Ext. 6190UK 011-44-734-774-868

4-12

APPENDIX A

TECHNICAL CHARACTERISTICS

Item Specifications

Physical

Plug-in moduleHeight 0.87 in. (22 mm)Width 10.5 in. (267 mm)Depth 10.75 in. (273 mm)Weight 1 Ib 3 oz (0.54 kg)Shipping weight 2 Ib 3 oz (1.0 kg)

Standalone installationHeight 3.9 in. (99 mm)Width 10.9 in. (277 mm)Depth 12.5 in. (318 mm)Weight 7 Ib 1 oz (3.2 kg)Shipping weight 8 Ib 1 oz (3.7 kg)

Environmental

Temperature, rackmountOperating 32° to 122°F (0° to 50°C)Non-operating -40° to 185°F (-40° to 85°C)

Temperature, standaloneOperating 32° to 122°F (0° to 50°C)Non-operating -40° to 158°F (-40° to 70°C)

Humidity, operating 5% to 95% without condensationAltitude

Operating 0 ft to 10,000 ft (0 m to 3,047 m). Derate by 1°C/1000 ft above sea level.Non-operating 0 ft to 40,000 ft (0 m to 12,191 m)

Electrical

Power requirements Rated: ±12 V dc, +5 V dc, 10 W maximum per card edgeVoltage 105-129 V acFrequency 50/60 HzInternal on-board power supply 22 V ac, 60 Hz, 24 VAPower dissipation

Standalone 8 W maximumRackmount 5 W maximum

FusingPlug-in module Two 1.5 A, 250 V, 3AG (GDC Part No. 215-150)Enclosures See respective enclosures for fusing requirements

Safety protection UL listed and CSA approved

A-1

TECHNICAL CHARACTERISTICS

Item Specifications

Electrical (Cont.)

Compatibility Fully compliant with Bell Pub. 62310 and ANSI T1.410 standardsOperating mode

Conventional DDS Full-duplex, point-to-point/multipoint64 kbps DDS Full-duplex, point-to-point

Data formatAsynchronous Binary, serial; 8-11 bits/character (CCITT V.14 compliant)Synchronous Binary, serial

Overspeed correction 1 or 2.3%Data encoding Bipolar, return-to-zeroData rate

Asynchronous 1.2,1.8, 2.4, 4.8, 9.6 or 19.2 kbpsSynchronous 2.4,4.8, 9.6,19.2, 56, 64 kbps

Line requirement Four-wire, non-loaded metallic circuit (19-26 ga)Line impedance 135 ohms ±20% (nominal)DTE interface EIA/TIA-232-E, CCITT V.35, or optional EIA-530Transmit power

2.4, 4.8,19.2, 56 and 64 kbps 6.0 dBm, maximum (50% duty cycle, random bipolar sequence, 135-ohmimpedance)

9.6 kbps 0 dBm maximum (50% duty cycle, random bipolar sequence,135- ohm impedance)

RTS-CTS delay2.4 kbps 8 ms nominal4.8 kbps 4 ms nominal9.6 kbps 2 ms nominal19.2 kbps 1 ms nominal56 kbps 0.35 ms nominal64 kbps Constant CarrierExtended RTS-CTS delay 45 ms nominal

Transmitter timing Receiver (slave/network), internal (DSU) ± 0.01%, or external (DTE) ± 0.02%Receiver dynamic range 48 dB extended range at 56 kbpsRange

Line data rate Maximum mileage with 26 ga cable2.4 kbps 11.5 mi (18.5 km)4.8 kbps 8.7 mi (14 km)9.6 kbps 6.1 mi (9.8 km)19.2 kbps 5.0 mi (8.1 km)56 kbps 3.6 mi (5.8 km)64 kbps 3.2 mi (5.2 km)

A-2

APPENDIX B

BUSINESS EQUIPMENT (DTE)INTERFACE SIGNALS (EIA/TIA-232-E)

PinNo. EIA CCITT DSU Name Description

2 BA 103 SD Transmitted data Transfers data signals from DTE for modulation and transmis-sion over communications line.

3 BB 104 RD Received data Transfers data signals to DTE that were received over commu-nications line and demodulated by DSU.

4 CA 105 RS Request to send Indicates to DSU that DTE is prepared to transmit.5 CB 106 CS Clear to send Indicates to DTE that DSU is prepared to transmit.6 CC 107 DSR Data set ready Indicates to DTE that DSU is prepared for data communica-

tions.7 AB 102 SIG

GNDSignal ground Establishes a common ground reference for all interface cir-

cuits except protective ground.8 CF 109 CO Received line signal

detectorIndicates to DTE that DSU is receiving data (not receiving idleor OOS codes).

9 +12 V +12 volts +12 V supply10 –12 V –12 volts –12 V supply15 DB 114 SC Transmitter signal

element timingTransfers transmitter signal timing information from DSU toDTE.

17 DD 115 RC Receiver signal ele-ment timing

Transfers receiver signal timing information from DSU to DTE.

18 LL 141 ALE Analog Loopbackenable

Transfers signal from DTE to control analog loopback test if op-tion switch S7-1 is ON.

20 CD 108/2 TR Data terminal ready Indicates to DSU that DTE is prepared for data communica-tions.

21 RL 140 RLE Remote DigitalLoopback enable

Transfers signal from DTE to control Remote Digital Loopbacktest mode if option switch S7-2 is ON.

24 DA 113 TC Transmitter signalelement timing(External Clock)

Transfers transmitter signal timing information from DTE toDSU.

25 TM 142 TME Test mode indicator Indicates to DTE that DSU is in a test mode if option switch S7-3 is ON.

B-1

APPENDIX C

BUSINESS EQUIPMENT (DTE)INTERFACE SIGNALS (CCITT V.35)

V.35Pin CCITT EIA DSU Signal DescriptionB 102 AB Signal ground Establishes a common ground reference for all interface cir-

cuits except protective ground.C 105 CA RS Request to send Indicates to DSU that DTE is prepared to transmit.D 106 CB CS Clear to send Indicates to DTE that DSU is prepared to transmit.E 107 CC DSR Data set ready Indicates to DTE that DSU is prepared for data communica-

tions.F 109 CF CO Received line signal

detectorIndicates to DTE that DSU is receiving data (not receiving idleor OOS codes).

K 142 TM TME Test mode indicator Indicates to DTE that DSU is in a test mode if option switch S7-3 is ON.

L 141 LL ALE Analog Loopbackenable


PS

103103

BA(A)BA(B)

SD-ASD-B

Transmitted data Transfers data signals from DTE for modulation and transmis-sion over communications line.

RT

104104

BB(A)BB(B)

RD-ARD-B

Received data Transfers data signals to DTE that were received over commu-nications line and demodulated by DSU.

UW

113113

DA(A)DA(B)

TT-ATT-B

Transmitter signalelement timing(External Clock)


VX

115115

DD(A)DD(B)

RT-ART-B

Receiver signal ele-ment timing


YAA/a

114114

DB(A)DB(B)

ST-AST-B

Transmitter signalelement timing

Transfers transmitter signal timing information from DSU toDTE.

BB/b 140 RL RLE Remote DigitalLoopback enable


H 108/2 CD TR Data terminal ready Indicates to DSU that DTE is prepared for data communica-tions.

C-1

APPENDIX D

BUSINESS EQUIPMENT (DTE)INTERFACE SIGNALS (EIA-530)

P1PIN

EIA CircuitDesignation Signal Description

1 — Shield Allows shield connections.214

BA(A)BA(B)

Transmitted data Transfers data signals from DTE for modulation and transmis-sion over communications line.

316

BB(A)BB(B)

Received data Transfers data signals to DTE that were received over commu-nications line and demodulated by DSU.

419

CA(A)CA(B)

Request to send Indicates to DSU that DTE is prepared to transmit.

513

CB(A)CB(B)

Clear to send Indicates to DTE that DSU is prepared to transmit.

622

CC(A)CC(B)

Data set ready Indicates to DTE that DSU is prepared for data communica-tions.

2023

CD(A)CD(B)

Data terminal ready Indicates to DSU that DTE is prepared for data communica-tions.

7 AB Signal ground Establishes a common ground reference for all interface cir-cuits except protective ground.

810

CF(A)CF(B)

Received line signaldetector

Indicates to DTE that DSU is receiving data (not receiving idleor OOS codes).

1512

DB(A)DB(B)

Transmitter signal el-ement timing

Transfers transmitter signal timing information from DSU toDTE.

179

DD(A)DD(B)

Receiver signal ele-ment timing


18 LL Analog Loopback en-able


21 RL Remote DigitalLoopback enable


2411

DA(A)DA(B)

Transmitter signal el-ement timing (ExternalClock)


25 TM Test mode indicator Indicates to DTE that DSU is in a test mode if option switch S7-3 is ON.

D-1

APPENDIX E

GLOSSARY

Address A sequence of bits, a character, or a group of characters that identifies a networkstation, user, or application; used mainly for routing purposes.

AL Analog Loopback.

Analog Transmission employing variable and continuous waveforms to represent infor-mation values.

Analog Loopback Technique for testing transmission equipment and devices that isolates faults tothe analog signal receiving or transmitting circuitry; a device, such as a modem,echoes back a received (test) signal that is then compared with the original sig-nal.

ANALOOP® General DataComm's version of Analog Loopback Test.

Asynchronous Transmission that is not related to a specific frequency or to the timing of thetransmission facility; transmission characterized by individual characters orbytes with start and stop bits from which a receiver derives the necessary timingfor sampling bits; start-stop transmission.

AsynchronousTransmission

Serial transmission of data in which each character is individually synchronizedby the use of start and stop bits. A start bit precedes and one or more stop bits followcontinuous information bits. Also called start-stop transmission. There is no def-inite time relationship between transmission of successive characters.

Auto-Rate Automatic data rate selection. The DSU automatically selects the data rate fortransparent service upgrades between subrates, as well as for upgrades from sub-rate to high speed (56/64 kbps) operation, by adjusting its rate to match that of theincoming network signal. The DSU continually attempts to Auto-Rate on power-upor when the line signal was absent for longer than 10 seconds and recovered.

Baud The maximum number of signaling elements, or symbols, per second that aregenerated; may be different from bps rate as several bits may be encoded persymbol, or baud, with advanced encoding techniques such as phase-shift keying.

BERT Bit Error Rate Test, or tester.

Bipolar The predominant signaling method used for digital transmission services, suchas DDS and T1, in which the signal carrying the binary value successively al-ternates between positive and negative polarities. Zero and one values are repre-sented by the signal amplitude at either polarity, while no-value “spaces” are atzero amplitude; also, polar transmission.

Bisynchronous A Binary Synchronous Communications protocol (BISYNC) that uses specialcharacters to define the various fields of a message and for control functions.Typically used for transmission between a CPU and a CRT or batch-type proces-sor. BISYNC accommodates a variety of transmission codes including ASCII,EBCDIC, and SBT (Six-Bit Transcode).

Bit A binary digit, the representation of a signal, wave, or state, as either a binaryzero or a one.

E-1

GLOSSARY

Bit Error Rate (BER) The percentage of received bits that are in error, relative to a specific amount ofbits received; usually expressed as a number referenced to a power of 10; e.g., 1 in

105.

Bps Bits per second; basic unit of measure for serial data transmission capacity; alsokbps (kilobits), for thousands of bits per second; Mbps (megabits), for millions ofbits per second; Gbps (gigabits), for billions of bits per second; Tbps (terabits), fortrillions of bits per second.

Buffer A storage device used to compensate for differences in the rate of data flow whentransmitting data from one device to another.

Byte Generally an 8-bit quantity of information, used mainly in referring to paralleldata transfer, memory capacity, and data storage; also generally referred to indata communications as an octet or character.

Carrier Detect An EIA/TIA-232-E Interface modem signal that indicates to the attached terminalthat a modem is receiving a signal from the remote modem.

CCITT International Telegraph and Telephone Consultative Committee (from theFrench, Comité Consultatif International Télégraphique et Téléphonique.)

Channel Part of a circuit path through several entities in a communication system. Achannel runs between two nodes.

Channel Service Unit(CSU)

A component of customer premises equipment (CPE) used to terminate a digitalcircuit, such as DDS or T1, at the customer site; performs certain line-condition-ing features, ensures network compliance per FCC rules, and responds to loop-back commands from central office; also, ensures proper ones density in trans-mitted bit stream and performs bipolar violation correction.

Character Standard bit presentation of a symbol, letter, number, or punctuation mark.

Character Code One of several standard sets of binary representations for the alphabet, numerals,and common symbols, such as ASCII, EBCDIC, BCD.

Character Oriented Describing a communications protocol or transmission procedure that carriescontrol information encoded in fields of one or more bytes.

Clear To Send (CTS) A signal indicating to the terminal that a modem is ready to transmit.

Clear To Send Delay The time required by a modem to inform a terminal device that it is ready to sendor reply to information just received.

Clock An oscillator-generated signal that provides a timing reference for a transmis-sion link; used to control the timing of functions as sample interval, signalingrate, and duration of signal elements; an “enclosed” digital network typicallyhas only one “master” clock.

Common Carrier In the United States, any supplier of transmission facilities or services to the gen-eral public that is authorized to provide such facilities or services by the appropri-ate regulatory authority and bound to adhere to the applicable operating rules, suchas making services available at a common price and on a nondiscriminatory ba-sis.

Constant Carrier Operation in which the Clear to Send signal from the modem to the terminal isheld permanently on and the modem's transmit carrier is always on. Carrierstays on independent of Request to Send from the data terminal; also continuouscarrier.

E-2

GLOSSARY

Control Characters Any transmitted characters, not message or user data, used to control or facilitatedata transmission between data terminal equipment (DTE); includes extra char-acters associated with addressing, polling, message delimiting and blocking,framing, synchronization, and error checking.

Controlled Carrier When Controlled Carrier is selected, the modem's transmit carrier is turned onand off by Request To Send (CA) from the terminal. The physical carrier signalis impressed on the line and the terminal is allowed to pass data after the ClearTo Send delay.

Convergence Display Oscilloscope display pattern from optional Constellation Pattern Generator whichindicates the rate at which the adaptive equalizer in the modem's receiver con-verges on received signals. This indication permits the identification of individ-ual malfunctioning remote stations or associated branch lines in multipoint net-works.

CS Clear To Send.

CSU Channel Service Unit.

CTS Clear To Send.

Data Digitally represented information, which includes voice, text, facsimile, andvideo.

Data Carrier Detect(DCD)

A signal sent from a data set which informs the terminal that a carrier waveformis being received; also called Carrier Detected, Carrier Found, Carrier On, etc.

DataCommonality General DataComm's term to describe a unique packaging technique that pro-vides (1) high density modular packaging, (2) a broad array of versatile data setsand accessories, (3) system flexibility and ease of expansion, (4) low power con-sumption, (5) heat dissipation, (6) quick and simple installation, (7) at-a-glancemonitoring of system operation, (8) convenient, low-cost maintenance, and (9)high reliability.

Data Communications Transmitting and receiving coded digital signals between computers or otherdigital devices or systems according to agreed upon specifications or standards.

Data CommunicationsEquipment (DCE)

Equipment that provides the signal conversion, connection control, and codingrequired for communication between data terminal equipment and data circuits;may be independent (e.g., a modem) or an integral part of a computer.

DATALOOP® General DataComm's version of Digital Loopback test.

Dataphone A service and trademark of AT&T; generically refers to the transmission of dataover the phone network (Dataphone Digital Service, or DDS), or to equipment fur-nished by the telephone company for data transmission.

Data Service Unit Component of customer premises equipment (CPE) used to interface to a digitalcircuit, such as DDS and T1; now generally combined with a CSU; performs con-version of customer's data stream to bipolar format for transmission.

Data Set A modem; term infrequently used except within the telephone carrier industry.

Data TerminalEquipment (DTE)

Generally end-user devices, such as terminals and computers that connect toDCE, which either generate or receive the data carried by the network; inEIA/TIA-232-E connections, designation as either DTE or DCE determines sig-naling role in handshaking; in a CCITT X.25 interface, the device or equipmentthat manages the interface at the user premises.

E-3

GLOSSARY

Data Terminal Ready(DTR)

A signal from the terminal to the modem indicating that the terminal is ready toreceive and transmit.

dB Decibel; a unit of measurement used to express the ratio of two values, usually thepower of electrical or electromagnetic signals; equal to 10 times the logarithm de-rived from a ratio of the two power levels, which are expressed in watts; the rela-tive gain or loss of a signal when the measured signal value is compared in a ra-tio to another, usually its input, value.

dBm Decibel reference to one milliwatt; relative strength of a signal, calculated indecibels, when the signal is compared in a ratio to a value of one milliwatt; usedmainly in telephony to refer to relative strength of a signal (e.g., at 0 dBm, a sig-nal delivers 1 milliwatt to a line load, while at -30 dBm a signal delivers 0.001milliwatts to a load).

DDS Dataphone digital service; private-line digital service offered intra-LATA byBOCs, inter-LATA by AT&T Communications, with data rates typically at 2.4,4.8, 9.6, and 56 kbps; now a part of the services listed by AT&T under the Accunetfamily of offerings.

Diagnostics Tests used to detect malfunctions in a system or component.

Digital Techniques and equipment in which information is encoded as either a binary“1” or “0”; the representation of information in discrete binary form, discontinu-ous in time, as opposed to the analog representation of information in variable,but continuous waveforms.

Digital Loopback(DL)

Technique for testing the digital processing circuitry of a communications de-vice; may be initiated locally or remotely via a telecommunications circuit; de-vice being tested will echo back a received test message, after first decoding andthen re-encoding it, the results of which are compared with the original message.

DSU Data Service Unit.

DTE Data Terminal Equipment.

Duplex Transmission Simultaneous two-way independent transmission in both directions. Also calledfull duplex transmission.

EIA Electronic Industries Association.

Equalization The process of reducing the effect(s) of amplitude frequency and/or phase distor-tion of a circuit by the introduction of networks to compensate for the difference inattenuation and/or time delay at the various frequencies in the transmissionbands.

External Modem A standalone modem, as opposed to a modem integrated within a computer orterminal.

Four-Wire Circuit Provision of two-wire pairs (or logical equivalent) for simultaneous two-waytransmission.

Ground An electrical connection or common conductor that, at some point, connects to theearth.

Half Duplex (HDX) Operational mode of a communications line where transmission occurs in eitherdirection, but not both directions simultaneously; transmission directions are al-ternately switched to accommodate two-way data flow.

E-4

GLOSSARY

Interface A shared boundary; a physical point of demarcation between two devices, wherethe electrical signals, connectors, timing, and handshaking are defined; the pro-cedure, codes, and protocols that enable two entities to interact for the meaningfulexchange of information.

LED Light-emitting diode.

Link The combination of communications devices, media and software intelligencethat is required to effect data communications.

Local Area Network A type of high-speed data communications arrangement wherein all segments ofthe transmission medium (typically, coaxial cable, twisted-pair wire, or opticalfiber) are under the control of the network operator.

Loopback Diagnostic procedure used for transmission devices; a test message is sent to adevice being tested, which is then sent back to the originator and compared withthe original transmission; loopback testing may be within a locally attached de-vice or conducted remotely over a communications circuit.

Modem Modulator/demodulator; electronic device that enables digital data to be sent over(typically) analog transmission facilities.

M R Modem Ready.

Multipoint Line A single communications channel (typically a leased telephone circuit) to whichmore than one station or logical unit are attached, though only one may transmitat a time; such arrangements usually require some kind of polling mechanism,under the control of a master station, to ensure that only one device transmitsdata at a time; also, a multi-drop line.

Network An interconnected group of nodes; a series of points, nodes, or stations connectedby communications channels; the assembly of equipment through which connec-tions are made between data stations.

Node A point where one or more functional units interconnect transmission lines(ISO); a physical device that allows for the transmission of data within a network;an end-point of a link or a junction common to two or more links in a network(IBM SNA); typically includes host processors, communications controllers, clus-ter controllers, and terminals.

Noise Any extraneous and unwanted signal disturbances in a communications link(e.g., electromagnetic interference; random variations in signal voltage or cur-rent or interfering signals.

Point to Point A circuit that connects two points directly, with generally no intermediate process-ing nodes or computers, although there could be switching facilities; a type of con-nection, such as a phone-line circuit, that links two, and only two, logical entities.

Private Line A leased line, an unswitched circuit.

RD Receive Data.

RDL Remote Digital Loopback.

Remote DigitalLoopback (RDL)

Similar to the Digital Loopback diagnostic test, except no modem operator is re-quired at the looping modem. With RDL, a signal is sent down the communica-tions line which instructs the remote modem to place itself in digital loopbackmode.

Request To Send A signal to the sending modem that the terminal is ready to transmit; part of mo-dem handshaking.

E-5

GLOSSARY

RTS Request To Send.

RTS-CTS Delay The delay between the time that the data terminal equipment asserts Request toSend (RTS) and the time that the modem asserts Clear to Send (CTS). Sets thetime delay or turnaround time from reception to transmission.

SD Send Data.

Self-Test A diagnostic test mode in which the modem is disconnected from the telephone fa-cility and its transmitter’s output is connected to its receiver’s input to permit thelooping of test messages (originated by the modem test circuitry) through the mo-dem to check its performance.

Send Data (SD) Send data from DTE to DCE.

Switched Network Communications link for which the physical path, established by dialing, mayvary with each use (e.g., a dial-up telephone circuit).

SynchronousTransmission

Data communications in which characters or bits are sent at a fixed rate, with thetransmitting and receiving devices synchronized, eliminating the need for startand stop bits necessary in asynchronous transmission and significantly increas-ing data throughput rates.

Terminal A point in a network at which data can either enter or leave; a device, usuallyequipped with a keyboard, often with a display, capable of sending and receivingdata over a communications link (IBM); generically the same as data terminalequipment (DTE).

Test Generator Allows the operator to select a 511 test pattern generator.

Transmission The dispatching of a signal, message, or other form of intelligence by wire, radio,telegraphy, telephony, facsimile, or other means (ISO); a series of characters,messages or blocks, including control information and user data; the signalingof data over communications channels.

Transparent Mode Transmission of binary data with recognition of most control characters sup-pressed. In binary synchronous communications, entry to and exit from thetransparent mode are indicated by a sequence beginning with a special character.

Two-Wire Circuit Usually a telephone circuit consisting of two insulated electrical conductors, typi-cal of most local loops.

E-6

INDEX

Analog Loopback test, option selection for DTE controlof, 2-5

Overspeed option selection, 2-7Permanent RTS option selection, 2-6

Anti-Streaming option selection, 2-6 Preoperational check, 2-1Auto-Rate option selection, 2-5 Rackmount shelfBusiness equipment (DTE) electrical connections, 2-8

CCITT V.35 interface signals, Appendix C installation, 2-2connections, 2-8 operation, 3-1EIA-530 interface signals, Appendix D Remote LoopbackEIA/TIA-232-E interface signals, Appendix B Inhibit option selection, 2-7option selection for interface type, 2-5 Methods option selection, 2-7

CCITT V.35 option selection for DTE control of, 2-5interface signals, Appendix C Self-Test, 4-7option selection for interface type, 2-5 test, 4-4

Changes in service rate, 2-1 Timeout option selection, 2-7Checking the installation and line, 2-1 Remote Terminal test, 4-5Circuit Assurance option selection, 2-7 Self-Test Pattern option selection, 2-6Communications line Self-Tests, 4-6

checking the line, 2-1 Service and training, 1-2connections, 2-8 64K Scrambler option selection, 2-6transposed lines, 2-1 Standalone enclosure

CSU Loopback test, 4-9 electrical connections, 2-8CTS Delay option selection, 2-6 installation, 2-2Data mode (async/sync) option selection, 2-7 operation, 3-1Data Rate Adapter Card, 2-9 System Status option selection, 2-7Description, 1-1 Technical assistance procedure, 4-11Diagnostics, 1-1 Technical characteristics, Appendix ADSU Loopback test, 4-10 Test Mode Indicator, option selection for DSU control of,

2-5EIA-530Interface Card, 2-8, 2-9 Testsinterface signals, Appendix D Analog Loopback test, option selection for DTE

control of, 2-5option selection for interface type, 2-5EIA/TIA-232-E CSU Loopback test, 4-9

interface signals, Appendix B DSU Loopback test, 4-10option selection for interface type, 2-5 End-to-End Self-Test, 4-8

Electrical connections, 2-8 Line Loopback Self-Test, 4-6End-to-End Self-Test, 4-8 Line Loopback test, 4-3Features, 1-1 Remote Loopback Inhibit option selection, 2-7Front panel Remote Loopback Methods option selection, 2-7

controls, 3-1 Remote Loopback Self-Test, 4-7indicators, 3-1 Remote Loopback test, 4-4Inhibit option selection, 2-7 Remote Loopback test, option selection for DTE

control of, 2-5Ground option selection, 2-5Installation Remote Loopback Timeout option selection, 2-7

checking the installation, 2-1 Remote Terminal test, 4-5procedures, 2-1 Self-Test Pattern option selection, 2-6rackmount, 2-2 Self-Tests, 4-6standalone, 2-2 Test Mode Indicator, option selection for DSU

control of, 2-5Line Data Rate option selection, 2-5Line Loopback Self-Test, 4-6 Timing Source option selection, 2-6Line Loopback test, 4-3 Training, 4-12Operation, 3-1 Transmit Buffer Clock option selection, 2-6Options Transposed lines, 2-1

checking option selection, 2-1 Unpacking and handling, 2-1selection, 2-2, 2-5 — 2-7 Word Size option selection, 2-7

PATENT NOTICE

ANALOOP® is a patented method and apparatus of General DataComm, Inc. (U.S.Patent 3,655,915).

DATALOOP® is a patented method and apparatus of General DataComm, Inc. (U.S.Patent 3,769,454).

TRADEMARK NOTICE

®

and the following are Trademarks of General DataComm, Inc.

ACCULINE® LAN*TMS™

ANALOOP® MEGAMUX®

AUTOFRAME® MEGAMUX TMS®

BERT 901® MEGANET®

DATACOMM SECURE-PAK® MEGASPLIT®

DATALOOP® MEGASWITCH®

DATX® (Canada Only) MEGAVIEW®

DATX SWITCHING SYSTEM® MULTIMODEM®

DIGIDIAL® NETCON®

FIRST RESPONSESM NETSWITCH®

GDC™ NMC®

General DataComm® NMS® (Canada Only)General DataComm X-PRESS 24SM Quikshippers®

GEN*NET® SERVI-CHECK®

GEN*PAC® SERVI-SNAP®

KILOMUX® STATKAT® ( Canada Only)

WARRANTY NOTICE

WARRANTIES: General DataComm, Inc. (hereafter referred to as GDC), warrants thatits equipment is free from any defects in materials and workmanship. The warrantyperiod shall be one year from the date of shipment of equipment. GDC's sole obligationunder its warranty is limited to the repair or replacement of the defective equipmentprovided it is returned to GDC, transportation prepaid, within a reasonable period. Thiswarranty will not extend to equipment subjected to accident, misuse, or alterations orrepair not made by GDC or authorized by GDC in writing. THE FOREGOINGWARRANTY IS EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES,EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, WARRANTIES OFMERCHANTABILITY AND FITNESS FOR PURPOSE.

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