Rudimentary digital speech interpolation apparatus for compressing data on a plurality of channels is disclosed, which includes circuitry for receiving data bits and control bits for each channel. The presence of silence on each channel is determined in response to the received data bits and zero bits are allocated for any silent channel in a frame structure. In addition, circuitry also allocates x bits per channel for the data bits in an non-silent channel in the frame. At least six bits per channel are also allocated for the control bits in the frame. 4N such frames are grouped to form a multi-frame.