Patent ID: 8249242

Claim:
A method for secure call Dual-Tone Multi-Frequency (DTMF) signaling in a system, the method comprising: entering a telephone number of a destination device as a dial string of characters or digits in an originating device by a user; assigning the dial string to a predefined string length by the originating device, wherein the predefined string has a total length that is greater than the length of the entered dial string such that there will be at least one leading hexadecimal bit in the predefined string length that is not used when the entered dial string is converted to hexadecimal; converting the dial string to hexadecimal by the originating device, and placing a form of the hexadecimal into a predetermined location in the string by the originating device; appending a number of “one” bits in predetermined locations of the predefined string with the number indicating how many nibbles of the predefined string length are unused, if any, by the originating device, and appending the remaining unused bits in the predefined string to “zero” bits by the originating device; and sending, by the originating device, the encoded string to a gateway for connection to the destination device.