A voice channel data processor 207 and corresponding method 600 operable in a wireless communications unit's 200 receiver and transmitter to facilitate data transmission on a voice channel includes an encoder 301 for encoding data traffic as a transmit voice frame having a predetermined vocoder parameter and inserting the transmit voice frame into a stream of transmit voice frames with voice traffic and further includes a decoder 303 for parsing a stream of received voice frames to obtain a vocoder parameter for each, comparing the vocoder parameter for each received frame to the predetermined vocoder parameter, routing the received voice frame for processing as data traffic when the comparison is favorable, and otherwise routing the received voice frame for processing as voice traffic.