Abstract: The system first incorporates an encoder which utilizes a 1/2 rate convolutional encoder to encode the data and a supplementary coding system for converting the 1/2 rate coded data to a nominal 3/4 rate. Thereafter, in order that the encoded data fits within the fixed frame length which has been adopted as a standard for the present TDMA transmission system, a portion of the excess data in each frame of encoded data put out by the encoder must be deleted or punched out. These bits are spaced throughout the frame to minimize the effect of the punchout routine.On the decoding side of the system, bits must be reinserted in the same place where they were deleted in the encoder. Because these bits were removed at the encoder, the decoder cannot possibly know what they were. It is not important to know what they were, but rather when in the received bit stream they would have occurred. In these places, place holding bits that are marked as such are inserted.

Abstract: A TDMA terminal is disclosed having a plurality of terrestrial interface ports, and a plurality of modems for modulating preamble and port data onto a carrier and demodulating the received data transmitted via a satellite from the carrier wherein the interface ports and modems are fully connected over a common bus arrangement. The TDMA terminal controller defines the sequence of transmission (TX) and reception (RX) of information through these multiple ports and modems. The control sequencing selectively activates the ports and modems to accommodate current traffic requirements. This is achieved by presenting clock timing signals and port address signals repetitively to the ports during each transmission frame to couple the ports to the bus for transmit and receive information during the allocated burst intervals. This sequencing system adds or deletes bursts, for selectively defining the ports and modems to be coupled to the bus.