Abstract: The network comprises a two-wire bus (coaxial cable) and a source of synchronizing pulses connected to the bus for marking off TDM cycles of about 125 us duration comprising a control slot and 8 links, i.e. pairs of time slots. The bus links devices, each comprising a microprocessor, TDM interface, bus interface and audio circuits. To set up a call the calling microprocessor finds a non-busy link and addresses in the control slot the called device which acknowledges. The TDM interface of the called device transmits pulses in one slot of the selected link while the TDM interface of the calling device transmits pulses in the other slot of the selected link. The bus interface effects pulse width modulation and demodulation of the pulses for full duplex speech transmission. The microprocessor also sends and receives digital data by the omission of pulses representing 0 bits.