The duplex is a method of communication in which system can send and receive data bi directionally. A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The duplex systems are used in many communications networks and allow for a communication two way street between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field.
There are two types of duplex communications:
- Half duplex system.
- Full duplex system.
Half duplex system
The half duplex system provides for communication in both the directions but not a simultaneously. Half duplex systems are usually employed to protect bandwidth, since only a single communication channel is needed, which is shared alternately between the two directions. For example, a walkie-talkie requires only a single frequency for bidirectional communication.
Full duplex system
The full duplex system is sometimes called a double duplex system. The full duplex system allows communication in both directions and it allow at the same time. It consists of two simplex channels, a forward channel and a reverse channel, linking at the same points. The main problem of the full duplex mode of transmission is that we are using two channels due to this bandwidth should be decreased.