Abstract: A backplane communication system based on CSMA/CD protocol including a plurality of communication nodes and method of encoding/decoding data via backplane bus. Each communication node (1) has transmit and receive data links (2,3) connected to the backplane bus (8) via an encoder/decoder (4,5) and also has a transmitter/receiver (6,7) whereby all data transmitted by any node may be passed to the backplane bus and between all communication nodes. Each node is synchronized by the backplane clock (9), so that data may be transmitted and received by the communication nodes via the backplane bus in a synchronous mode. The encoder/decoder provides for detecting a collision on the backplane bus as well as for passing slot identification information between communication nodes.