Abstract: A telephone switching network is disclosed, which network is adapted to provide connections between a plurality of input subscriber lines. The network includes a time slot interchanger which comprises a transmit switch memory and a receive switch memory. The transmit and receive memories are capable of storing data at addressable storage locations, which data is indicative of digital data to be transmitted from a line circuit and digital data to be received by a line circuit during a connection between the two line circuits. A connect memory is also employed for storing data indicative of connections to be made between line circuits. The connect memory as well as the switch memories are controlled in operation by a processor, which processor includes an access control means.