A method for transferring data over a communication link using a data rate and a voice modem not designed to provide communications at the data rate, includes generating, in a processor, a modulated Frequency Shift Keying (FSK) signal from an outgoing data stream. The voice modem, in playback mode, plays the modulated FSK signal over the communication link. The voice modem, in record mode, receives voice data from the communication link and sends the voice data to the processor, which demodulates any FSK signal that is present in the voice wave data to produce an incoming data stream.