Multiplex and demultiplex transmission system for tropospheric link - has control obtained from microprocessor in frame control circuit acting on frame synchronising and descriptive elements

摘要

An interface upstream from a multiplexer/demultiplexer contains a number of subscriber circuit cards to which input and output lines are connected. These circuits provide signal matching for user appts. and also an internal information management circuit. Direct memory access is provided to the multiplexer. A frame controller receives the signals from the circuit cards on a bus to which a microprocessor is connected with its ROM and RAM. This receives the frame sync. signal and acts on description elements in the frame to perform the multiplexing process. A shaping circuit allows the data to be controlled prior to transmission of a frame through transmission/reception circuits. An interface allows a peripheral keyboard to be used to change the state of a channel.