A transceiver (34) includes a rate adaptation buffer (74) that synchronizes a data stream received at a 4.0 kHz rate to a data stream that is transmitted at a 4.05 kHz rate. A transmit section (62) of the transceiver (34) performs rate adaptation using a single rate adaptation buffer. The transmit section (62) includes four autonomous modules which are able to access the data in the rate adaptation buffer (74) independently of one another. These four modules include a CRC-scrambler (72), a FEC encoder (76), an interleaver (78), and a constellation encoder (80). A timing controller (84) prevents contention for accesses to the rate adaptation buffer (74). In addition, each of the four modules perform their respective functions quickly enough to prevent overflow or underflow conditions in the rate adaptation buffer (74). A receive section (64) functions similarly to the transmit section (62).