The highly integrated CMX989 CDPD MAC and Data Pump Processor integrates complex CDPD MAC and physical layer functions to serve as a core engine for high performance, low power CDPD terminal designs. MAC layer functions decouple the host CPU from the CDPD airlink to simplify and reduce CDPD protocol stack programming, free CPU capacity for applications, eliminate interface components, and allow CPU sleep time for power savings. Physical layer functions mate MAC layer to baseband radio signals with minimal host involvement. MAC and physical layer functions are intelligently coupled to meet airlink timing requirements. For example: Tx emissions automatically start in synchronisation with Forward Channel busy/idle status. The Rx CDPD frame FIFO is automatically managed to wait for valid synchronization to occur when first started and after lost signal recovery. The radio interface supports simple, low cost, VCO-based RF modulators and discriminator-based receivers. Independent, programmable gain Tx outputs are provided for software trimming and balancing of modulating signals. The host CPU interface is FIFO based and organized in CDPD frames, to provide a simple programming interface with low service latency requirements. Over-the-air frames are automatically encapsulated and de-encapsulated and include complete Reed-Solomon encoding, decoding and error correction, colour code insertion and related functions. Device status bits are accessible and may be individually configured to interrupt the host via the parallel hardware interface. The CMX989 operates from a 2.7V to 5.5V supply over -40 to 85C and comes in a 28-pin TSSOP package (CMX989E1).