cse, it iii sem course name-dac topic- communication modes

CSE, IT– III SEM

Course Name-DACTopic-

Communication modes

2

Digital and Analog Communication

Section C

Standards in data communication

SyllabusSection C: Standards in data communications:1. Communication modes: simplex, half duplex, full duplex;2. Transmission modes: serial-, parallel-transmission;

synchronizations: Asynchronous-, synchronous-transmission;

3. Type of services: connection oriented-, connectionless-services;

4. Flow control: unrestricted simplex protocol, simplex stop- and -wait protocol, sliding window protocol;

5. Switching systems: circuit switching; picketing switching: data gram , virtual circuits, permanent virtual circuits.

6. Telephone Systems: PSTN, ISDN, asynchronous digital subscriber line.

7. Multiplexing: frequency division-, time-, wave- division multiplexing

COMMUNICATION MODESCOMMUNICATION MODES

Modem

ModemDATA TRANSMISSION

MediaDTE 1

DTE 2


It defines the direction of signal It defines the direction of signal flow between two linked devices flow between two linked devices (transmitter and receiver).(transmitter and receiver).

A data A data transmission mode transmission mode is the manner in is the manner in which data is sent over the underlying which data is sent over the underlying mediummedium

DATA TRANSMISSION MODE


Simplex Half Duplex Full Duplex Full / Full Duplex






Simplex Half Duplex Full / Full Duplex


A communications mode is classified as under (depending on the direction of transfer of data )

9

A simplex mechanism can only transfer data in a single direction. Only one of the two devices on a link can transmit; other can only receive. Examples

a) broadcast radio or televisionb) Keyboard can only inputc) Monitor can only accept output.

The simplex mode uses the entire capacity of the channel to send data in one direction

Simplex Mode Communication

Simplex, Half-Duplex, and Full-Duplex Transmission

10

Full-Duplex MODE COMMUNICATION

allows transmission in two directions simultaneouslyIt is analogous to a voice telephone conversation in which a

participant can speak even if they are able to hear background music at the other end.

In full duplex mode. Signals going in one direction share the capacity with signal going in other direction.

The sharing can occur in two ways:Either the link must contain two physically separate paths,

one for sending and other for receiving orThe capacity of the channel is divided between signals

travelling in both directions.

12

Half-Duplex

A half-duplex mechanism involves a shared transmission medium The shared medium can be used for communication in both

direction but the communication cannot proceed simultaneously.

An additional mechanism is needed at each end of a half-duplex communication that coordinates transmission to ensure that only one side transmits at a given time

Entire capacity of a channel is taken by whichever of the two devices is transmitting at the time.

Walkie-talkies and CB radio - only one side can transmit at a time and are half duplex system.

allows communication in two directions at the same time but not between the same two stations.

Full/Full-Duplex MODE COMMUNICATION

Tx/Rx

Tx/Rx

Satl

No direct link

•One station sends to a second station and third station receives.•Used in multipoint communication systems

Simplex, Half-Duplex, and Full-Duplex Transmission

14

cse, it iii sem course name-dac topic- communication modes

Documents