Abstract: A method and apparatus are described for automatically generating the frame that is used in a bit-interleaved time division multiplexer (TDM). The apparatus comprises a microprocessor, two random access memories in which are stored the channel select signals, device for determining the transmission frequencies of each channel and a computer program which is stored in the memory of the computer for calculating the distribution of the channel select signals in the frame. With such a system, the frame can be reconfigured in about thirty seconds. Two random access memories are preferably used for the storage of the channel select signals. While the signals stored in one memory are being used to generate the actual frame, a new set of channel select signals can be stored in the other memory. After such an updated frame is written in the second memory, the task of generating the channel select signals can be switched from the first memory to the second memory without loss of any data from any of the data channels.

Abstract: A method and apparatus are described for ensuring that control signals from every data channel are transmitted periodically regardless of any change in these control signals. The apparatus comprises a counter for counting the number of control signals transmitted, decision logic for determining when it is time to transmit a set of control signals regardless of any change in these signals and circuitry for selecting the channel whose signals are to be transmitted. The apparatus provides additional equipment for determining when the control signals for a particular channel have changed and for transmitting such signals with suitable error checking. The apparatus also provides equipment for interleaving the two flows of control signals without loss of the control signals which are changed.