Data Communication & Data Transmission Modes

Data Communication

In data communication, four basic terms are used i.e.

→ Data

→ Signal

→ Signaling

→ Transmission

Data refers to information that conveys or contains something of meaning to source/recipient. The information in data may be raw data or contain interpreted result from raw data.

Signal is the data encoding in the form of electric or electromagnetic waves to produce digital or analog signal.

Signaling is the process by which computer interacts with transmission media & sends the signal down the media.

Transmission is the communication of data achieved by propagation or processing of signals.

Data Transmission Modes

There are three ways as modes for transmitting data from one point to another. These are:-

→ Simplex

→ Half-Duplex

→ Full-Duplex

Simplex Mode of Transmission

In Simplex transmission, communication takes place only in one direction. Devices connected to such a circuit are either send-only or receive only device.

Fig-1.1 -- Simplex Mode of Data Transmission

Half-Duplex Mode of Transmission

A Half-Duplex system can transmit data in both directions, but only one direction at a time. This requires two wires. This is a common type of communication because one person can speak at a time. In this case line must be turned around each time the direction is reversed. This involves a switching circuit.

Fig-1.2 -- Half-Duplex Mode of Data Transmission

Full-Duplex Mode of Transmission

A Full-Duplex system allows information to flow simultaneously in both the direction on the transmission path. Use of Full-Duplex line improves efficiency because the line turn around time is removed. It requires four wires.

Fig-1.3 -- Full-Duplex Mode of Data Transmission