Improvements in or relating to data interconnecting networks

A circuit for signal generation and synchronisation is disclosed for a ring network in which a number of stations communicate with each other. The circuit, which is provided at each station in the ring, includes a phase locked loop which loosely couples the transmit and receive clocks of each station during a repeater mode of operation. During a transmit mode the receive and transmit clocks are de-coupled so that phase delay around the ring does not degrade the transmission clock each time a transmission is initiated. The circuit includes logic gates for detecting the transmission of a token, means for generating a token and means for jam syncing the transmit and receive clocks to detect transitions in the incoming data during the repeater mode and after a token has been generated at the end of the transmit mode.