Transmission Modes in Computer Networks

In this tutorial, we will be covering the concept of transmission modes in Computer Networks.

Transmission mode refers to the mechanism of transferring data between two devices connected over a network. It is also called Communication Mode. These modes direct the direction of the flow of information.

In the Open System Interconnection(OSI) Model, the Physical Layer that is layer1 is mainly dedicated to data transmission in the network. It mainly decides the direction of data in which the data needs to travel in order to reach the receiver system.

There are three types of transmission modes. They are:

1. Simplex Mode

2. Half-duplex Mode

3. Full-duplex Mode

SIMPLEX Mode

In this type of transmission mode, data can be sent only in one direction i.e. communication is unidirectional. We cannot send a message back to the sender. Unidirectional communication is done in Simplex Systems where we just need to send a command/signal and do not expect any response back.

Examples of simplex Mode are loudspeakers, television broadcasting, television and remote, keyboard and monitor etc.

Simplex Mode is not so popular mode of transmission. This mode is more similar to the one-way street. The main use of this transmission mode is in the business field like sales that do not require any corresponding reply.

Advantages of Simplex Mode

Following are some of the advantages of Simplex Mode:

• As in simplex mode, data flows in one direction. So there is the least or no data traffic issue.

• Simplex Mode utilizes the full capacity of the communication channel at the time of data transmission.

Disadvantages of Simplex Mode

Some drawbacks of Simplex Mode are as follows:

• As communication is unidirectional in nature so there are no chances of inter-communication between devices.

• The Information cannot be transmitted back to the sender; thus there is no mechanism of acknowledgment

HALF DUPLEX Mode

Half-duplex data transmission means that data can be transmitted in both directions on a signal carrier, but not at the same time. In Half Duplex transmission mode, the entire capacity of the channel can be utilized for each direction. In this mode, the Transmission lines can carry the data in both directions, but the data can be sent only in one direction at a time.

For example, on a local area network using a technology that has a half-duplex transmission, one workstation can send data on the line and then immediately receive data on the line from the same direction in which data was just transmitted. Hence half-duplex transmission implies a bidirectional line (one that can carry data in both directions) but data can be sent in only one direction at a time.

An example of a half-duplex is a walkie-talkie in which a message is sent one at a time but messages are sent in both directions.

Half Duplex transmission mode can be used in those cases where there is no need for communication to occur in both directions at the same time. This mode can also be used for the error detection when the sender does not send or the receiver does not receive the data properly.

Advantages of Half-Duplex Mode

Following are some of the advantages of Half-duplex Mode:

• With the help of Half Duplex mode, the use of the communication channels is optimized.

• This mode provides two-way communication

Disadvantages of Half-Duplex Mode

Some of the drawbacks of half-duplex mode are as follows:

• The half Duplex mode supports two-way communication but this communication cannot be established simultaneously at the same time so this is the major drawback of using this mode.

• There are chances of delay in transmission because at a time only one-way communication is possible.

FULL DUPLEX Mode

In the full-duplex system, we can send data in both directions as it is bidirectional at the same time, in other words, data can be sent in both directions simultaneously.

This mode of transmission supports the two-way communication in which both the stations can transmit and receive the data simultaneously. Thus Full-Duplex mode provides the best performance among all.

An example of Full Duplex is a Telephone Network in which there is communication between two persons by a telephone line, using which both can talk and listen at the same time.

In the full-duplex system, there can be two lines one for sending the data and the other for receiving data.

The bandwidth of the Full-Duplex Mode is double as compared to the Half Duplex Mode. This mode is used at the time when communication is required in both directions simultaneously.

Advantages of Full-Duplex Mode

Following are some of the benefits of Full-duplex Mode:

• With the help of this mode, two-way communication can be carried out in both directions simultaneously.

• This mode is one of the fastest modes of communication between devices

Disadvantages of Full-Duplex Mode

Some drawbacks of full-duplex mode are as follows:

1. In this mode has the utilization of the bandwidth of the channel is improper and it is because of the due to the reason that there are two separate paths for the two communicating devices.

2. There is no dedicated path for data transfer. Also the capacity of the communication channel is divided into two parts.