Data Flow

Data Flow Communication between two devices can be simplex, half-duplex, or full-duplex.

Simplex: In the simplex mode, the communication is unidirectional, as a one-way street. This meant data flow takes place towards only one direction at a time. Only one of two devices on a link can transmit the data and the other can only receive . Keyboards and traditional monitors are examples of simplex devices. The keyboard can only support the input, the monitor can only accept output. The simplex mode can use the entire capacity of the channel to send data in one direction.

Half-Duplex In half-duplex mode, each node in the network can send and receive, but the same time. When one device is sending, the other can only receive, and the vice versa. The half-duplex mode is like one-lane road with traffic allowed in both directions. When cars are travelling in one direction, cars going the other way must wait. In a half-duplex transmission, the entire capacity of a channel is taken over by whichever of the two devices is transmitting at the time. Walkie-Talkie and CB (citizen band ) radios are both half-duplex systems.

Full-Duplex In full-duplex mode (also called duplex), both stations can transmit and receive simultaneously. The full-duplex mode is like a two-way street with traffic flowing in both direction at the same time. In full-duplex mode, signals going in one direction share the capacity of the link with signals going in the other direction. This sharing can occur in two ways; either the link must contain two physically separate transmission paths, one for sending and the other for receiving; or the capacity of the channel is divided between signals traveling in both directions.