Patent ID: 6493441
Filing Date: 2002-12-10
Classification: H04M,H04Q

Abstract:
A method for preventing an unauthorized calling party on a telephone network from controlling apparatus responsive to in-band signalling following the set up of a call, comprising:determining whether the calling party is authorized to use in-band signalling to control the apparatus following the set up of a call, where the determination is made by the telephone network; determining when the process of setting up a call has been completed; and in response to the determination that the calling party is not authorized to use in-band signalling following the set up of a call and the determination that the process of setting up a call has been completed, preventing the unauthorized calling party from using in-band signalling to control the apparatus, the step of preventing comprising the step of blocking transmission of at least one frequency selected from a group consisting of 697 Hz, 770 Hz, 852 Hz, 941 Hz, 1209 Hz, 1336 Hz, 1477 Hz, and 1633 Hz.