Patent ID: 8194779

Claim:
A method of communicating digital data via a wireless telecommunications network, comprising the steps of: modulating one or more carrier signals with digital data using differential phase shift keying modulation of the one or more carrier signals, thereby producing a modulated carrier signal; transmitting the modulated carrier signal between a call center and a telematics unit, wherein the transmitting step is carried out by sending the modulated carrier signal via a vocoder across a voice channel of a wireless telecommunications network; receiving the modulated carrier signal transmitted via the wireless telecommunications network; and demodulating the received modulated carrier signal back into the digital data; wherein the modulating step further comprises generating the modulated carrier signal as a composite modulated carrier signal by carrying out the steps of: modulating a first carrier signal having a first frequency with a portion of the digital data using differential binary phase shift keying modulation; modulating a second carrier signal having a second frequency with the remainder of the digital data using differential binary phase shift keying modulation; and combining the two modulated carrier signals into a composite modulated carrier signal.