Data Communication

☞ It is a two-way process in which messages are transferred from one person to another.

☞ Sender :

• Send the data.

☞ Receiver :

• Receives the data.

☞ Message :

• Information to be communicated.
• Examples - text, image, audio, etc.

☞ Transmission Medium :

• Physical path that carries information.
• Examples - cable, wires or waves,etc.

☞ Protocols :

• Set of rules that govern communication.

☞ Simplex :

• It sends the message only in one direction.
• Examples - radio stations and tv.

☞ Half-duplex :

• It sends the message in both directions but permits only one direction at a time.
• Examples - walkie-talkie.

☞ Full-duplex :

• It sends the message in both directions at the same time.
• Examples - mobile phone and landline.

☞ Channel :

• Communication path through which data is transmitted.

☞ Baud :

• It is the number of changes in a signal per second.
• It is the measuring unit of data transfer rate.
• 1 Baud = 1 signal change per second = 1 Bit per second

☞ Bits per second :

• It is the measuring unit of speed.

☞ Bandwidth :

• It is the amount of data which can be transmitted in each amount of time.

☞ Data and Signals :

• Data are entities that are stored in the form of 0’s and 1’s.
• Signals are the electromagnetic encoding of data that used to transmit data.

☞ Communication/Transmission Media :

• It is a way of transmitting the signal from one place to another.

☞ Data Transfer Rate :

• It is the amount of digital data transferred per second.
• The measuring units are bits per sec (bps), Bytes per sec (Bps), Kbps, Mbps, Gbps, Tbps.