Abstract: A system and method for selecting and generating telephone access numbers for limiting access to a telephone service. The system includes an auto-dialer having a system clock, a memory device, a processor, and a tone generator. The auto-dialer is used to transmit user-associated data to a telephone service. The system clock generates a system time and the memory device stores data and a plurality of telephone numbers, each of which is capable of accessing the telephone service at different times. The processor is electrically coupled to the system clock and to the memory device and can select the telephone number capable of accessing the telephone service at any moment in time as a function of the system time. The auto-dialer can also include a number generator operating according to a preselected pseudo random sequence, in electrical communication with the system clock and the processor, where the output of the system clock is used as a seed number to the number generator.

Abstract: An auto-dialer suitable for use as a smart card capable of being acoustically coupled to a telephone and being reprogrammed in response to acoustic signals. The programming and other features of the auto-dialer can be enabled or disabled by the auto-dialer in response to persecuted signals, e.g., a string of DTMF tones. Encryption of calling card and other data into destination telephone numbers is achieved by selectively altering persecuted characteristics of a DTMF tone sequence, such as the duration of tones, the period of silence between tones and the twist between Lo-band and Hi-band tones of DTMF tone pairs in a DTMF tone sequence representing a telephone number. The encryption of data into the telephone number does not affect the ability of standard telephone switching circuitry to recognize the destination number.