Preventing generation of spurious signals during transmission

1. A method of establishing a data connection over a voice channel via a cellular communication network, comprising the steps of:

establishing a voice channel connection over a wireless carrier system; and

creating a data connection over the established voice channel connection using the step of transmitting a signaling waveform over the voice channel between a first wireless modem at a vehicle and a second wireless modem remotely located from the vehicle, wherein the creating step includes, prior to transmitting the signaling waveform from the first wireless modem, generating the signaling waveform at the vehicle by:

providing from an audio modem that is located in the vehicle a signal comprising one or more frequencies, wherein the signal varies in amplitude, frequency, phase, or any combination thereof without exhibiting periodic nullities;

providing the signal as an input to a vocoder in the vehicle; and

providing an output of the vocoder to the first wireless modem for transmission of the signaling waveform to the second wireless modem.

2. The method according to claim 1 , wherein the vehicle comprises a telematics unit that comprises the first wireless modem.

3. The method according to claim 1 , wherein the creating step further comprises transmitting the signaling waveform from the first wireless modem to the second wireless modem as a calling waveform.

4. The method according to claim 3 , further comprising the step of receiving at the first wireless modem a response waveform sent by the second wireless modem.

5. The method according to claim 4 , wherein the response waveform received by the first wireless modem is associated with a second signal generated at a data server that varies in amplitude, frequency, phase, or any combination thereof and does not exhibit periodic nullities, wherein the second signal is provided to another modem and vocoder located at the data server prior to being sent by the second wireless modem.

6. The method according to claim 4 , further comprising the step of terminating the calling waveform in response to the receipt of the response waveform.

7. A method of establishing a data connection over a voice channel via a cellular communication network, comprising the steps of:

establishing a voice channel connection over a wireless carrier system; and

creating a data connection over the established voice channel connection using the step of transmitting a signaling waveform over the voice channel between a first wireless modem and a second wireless modem, wherein the signaling waveform varies in amplitude, frequency, phase, or any combination thereof without exhibiting periodic nullities,

wherein the creating step further comprises transmitting the signaling waveform from the first wireless modem to the second wireless modem as a calling waveform,

wherein the calling waveform has a frequency of 2225 Hz and wherein approximately every 100 milliseconds, the calling waveform includes phase shifts of the frequency that occur alternately and repetitively between a positive shift of 90 degrees and a negative shift of 90 degrees.

8. The method according to claim 1 , further comprising:

terminating the data connection and the voice channel connection between the first and second wireless modems;

thereafter, establishing a second voice channel connection over the wireless carrier system; and

creating a second data connection over the second voice channel connection, wherein the second wireless modem transmits a calling waveform to the first wireless modem and, based on the calling waveform, receives a response waveform, wherein the calling and response waveforms are associated with respectively different signals that vary in amplitude, frequency, phase, or any combination thereof without exhibiting periodic nullities.

9. The method according to claim 8 , further comprising the step of terminating the calling waveform sent by the second wireless modem in response to the receipt of the response waveform from the first wireless modem.

10. A method of establishing a data connection over a voice channel via a cellular communication network, comprising the steps of:

establishing a voice channel connection over a wireless carrier system; and

creating a data connection over the established voice channel connection using the step of transmitting a signaling waveform over the voice channel between a first wireless modem and a second wireless modem, wherein the signaling waveform varies in amplitude, frequency, phase, or any combination thereof without exhibiting periodic nullities,

wherein the creating step further comprises sending a calling waveform from the first wireless modem to the second wireless modem and, in response, sending the signaling waveform as a response waveform from the second wireless modem to the first wireless modem,

wherein the response waveform is a single frequency of 1556 Hz and wherein approximately every 100 milliseconds, the response waveform includes phase shifts of the frequency that occur alternately and repetitively between a positive shift of 90 degrees and a negative shift of 90 degrees.

11. The method according to claim 1 , wherein the establishing step further comprises establishing the voice channel connection over a wireless communication system using cellular network modems and wherein the signaling waveform is sent over the voice channel between the first and second modems via the network modems.

12. The method according to claim 1 , wherein the step of providing a signal from an audio modem further comprises providing a signal having at least one frequency that includes phase shifts.

13. The method according to claim 1 , wherein the signaling waveform includes random audio tones that do not exhibit periodic nullities and that lessen or avoid echo cancellation at the vocoder.