in-house cabling solutions

1Torino, 30-31 March 1998

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In-house cabling solutions

Giuseppe A. AZZINI, Francesco CAVIGLIA, Giuseppe GALLIANO and Adler TOFANELLI

CSELT S.p.A. Torino - Italy

ANCITTorino, 30-31 March 1998


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Summary• Introduction

• The services for the residential customers

• Home network topologies

• Cabling solutions for the new buildings

• Cabling solutions for already existing buildings

• Cables and components

• Economical evaluation

• Conclusions


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Why “In-house cabling” is so important

• Strong impact on the final residential customer for:– costs

– unaesthetic presence of cabling infrastructures

• The success of the new services depends on customer premises cabling issues

• The solution are:– infrastructure/wiring guidelines for new buildings

– suitable cabling systems for already existing buildings

– new technologies for providing services (radio, use of power wiring...)


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Services • The Italian present situation

– POTS

– ISDN

– TV (Terrestrial Radio Broadcast)

– CATV (HFC network)

– SAT-TV (Satellite Radio Broadcast)

• The future– Evolution of the already existing services

– Switched Digital Video Broadcasting (SDVB) using xDSL techniques

– Fast Internet (xDSL, Cable Data Modem, satellite access...)

– Home automation

– ?


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Services present situation

coax

coax

Twisted pairs

FN

= POTS= TAP

POTS

coax

ISDN

= ISDN NT

Modem

HFC network


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New services

coax

coax

Twisted pairs

FN

= POTS

= Combiner/splitter

= TAP

POTS

coax

ISDN

= ISDN NT

CDM

POTS

xDSL

= xDSL NT

HFC network

xDSL

ISDN


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Home Network Topologies

• Star

– SDVB, Fast Internet (ATM 25 Mbit Ethernet)

– POTS (not in Italy)

– More flexible

• Bus

– POTS (Italian Specs.)

– ISDN (S-Bus)

– TV/CATV Satellite (most used in Italy)

– Minimum wiring length


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Cabling solutions for new buildings

• Guidelines for the new infrastructures

• Choice between:

– “infrastructure-only” approach (ducts and outlets position)

– “wiring” approach (type and number of cable to each outlet)

• In-chase ducts are mainly used (for brick walls)

• Critical issues are the number of outlets and the ducts

dimension (number of installed cables for the second

approach)


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Italian guidelines for new buildings– “Infrastructure only” approach

– Star for future Broadband services

(20 mm tube, 1 outlet/room)

– Bus for POTS and ISDN

(20 mm tube, 1 outlet/room)

– Presence of a box at the star centre

size: (300x200x80 mm)

External diameter 20 mm

Internal diameter 14.1 mm

Usable diameter 10.8 mm

Coax

UTP

POF

– The convenience for ducts larger than

20 mm is under consideration

A 20 mm duct completed filled


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U.S.A. national standard (draft EIA/TIA 570)“Residential Telecommunications cabling standard”

• “Wiring” approach• Star topology• 3 different cabling grades

Grade 1 : 1 x 75 coax 2 x twisted pair (UTP cat.3)

Grade 2 : 2 x 75 coax x twisted pair (UTP cat.3)

Grade 3: 2 x 75 coax 2 x twisted pair (UTP cat.5) optical fibres (optional)

• Wall space at the star centre for a distribution device(e.g. 0.8x0.9 m for a grade 2 cabling)

• “Wiring” approach requires the installation of a large number of cables

• Rules coordinated with the “Residential Gateway” approach


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Cabling solutions for Existing Buildings

• In-chase ducts technique is not viable for costs and inconveniences

• Suitable techniques are:

– raceways

– Wall direct riveting

• The main purpose is to provide the link when needed:– Raceway solution allows a sharing of the infrastructure for future

upgrading

– Raceways have a stronger aesthetic impact but new products are coming

– No strong differences among cable types (optical, UTP, coax..)


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Coaxial Cables and Components

5 MHz 1 GHz 2.5 GHz

5 MHz 1 GHz 1 MHz

Used for CATV distribution (5 -1000 MHz)

Opportunity: Open to the satellite band But: Cost increase

Opportunity: Open to low frequency But: Non standard VDSL signals branching devices


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Coaxial cabling used for low frequencyVDSL signals (e.g. DAVIC solution)

CATV(50 MHz to 1 GHz) VDSL (1 to 30 MHz)

COMBINERTAP Oultlet

Outlet

Outlet

TV Set top box

PC VDSL terminal


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Silica or Plastic Optical Fibres and connectors

Poly Methyl Maethacrylate (PMM)

Fluorinate Polymer

970 m1000 m

•Step index Plastic Optical Fibre•Acceptable transmission performances•Easy to be connected (low cost)

•Silica Fibre for low cost applications: multimode 62.5 m•Good transmission performances•Low cost connectors are appearing on the market


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Optical cables for residential applications

• Cables to be pulled in ducts– Tensile resistance is important

• Cables to be installed in raceways– Small size is important

• Cables for direct riveting to wall– Crush resistance is important

• Under carpet cables– Flat, good crush resistance

FO have small intrinsic dimensions, but require adequate protectionThe optimum cable structure depend on the installation method

Coiled steel

Aramidic yarns (e.g. Kevlar)

About 1 mm

3.8 mm


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An economical evaluation• The economical impact of the cabling for broadband (BB)

outlets using:– Different Infrastructure solutions

• In-chase ducts (a new building with pre-installed ducts is presumed)

• Raceways

• Wall riveting

– Different cables

• UTP (Cat. 5)

• Silicon multimode fibre (62.5 m core)

• Plastic Optical Fibre

• Evaluation based on an example with:– Installation of 2 BB outlets (at time 1) and 2 further BB outlets (at time 2)


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An economical evaluation (2 outlets)

• Time 1 - Total cost (in Euro) for two BB outlet

• The cost for the Ducts solution includes the cost of pre-installed ducts for 8 potential outlets (325 Euro)

Ducts

Raceway

Wall

UTP

Si Fibre

POF

0

200

400

600


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An economical evaluation (upgraded to 4 outlets)

Ducts

Raceway

Wall

UTP

Si Fibre

POF

0

200

400

600

• Time 2 - Total cost (in Euro) after the addition of 2 further BB outlets

• The cost for the Ducts solution includes the cost of pre-installed ducts for 8 potential outlets (325 Euro)


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An economical evaluation (discussion)• In-chase ducts solution is the more expensive.

(However: most of the cost is in the pre-installed duct infrastructure, that often can be regarded as an investment, as it grants elasticity and increases the value of the the house)

• Direct wall riveting is the cheaper solution

• The Si Fibre solution appears to be more expensive than UTP or POF solution.(However: the difference arises from the cost of connectors;the foreseeable venue of cheaper connectors will close the gap)

• The cost does not strongly depend on the physical carrier (UTP, Si fibre, POF); hence the driving force in choosing it is not the economical aspect


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Conclusions

• For the in-house-cabling, three main techniques are available: in-chase ducts, raceways, direct riveting

• For new building the future development of the services requires a guideline on the cabling infrastructure

• For already existing building only raceway and direct riveting are applicable, but with a negative impact on the aesthetic

• The costs of the in-chase ducts technique are higher than the others, but with advantages in elasticity and aesthetic

• The cost of the cabling does not notably depend on the physical carrier (UTP, Si fibre or POF)

in-house cabling solutions

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