A data storage area allows a user of a wireless communication device to enter data to be processed and transmitted as a series of dual-tone multi-frequency (DTMF) tones. A wireless communication device transmits call origination over the traffic channel and can transmit DTMF tones over the traffic channel....http://www.google.co.uk/patents/US6542732?utm_source=gb-gplus-sharePatent US6542732 - System and method for use of dual-tone multi frequency signals in a wireless communication system
