Importance

Loading Importance Indicators...

Abstract

Potentially fraudulent telephone calls are intercepted from public telephones. As the digits which correspond to a telephone number are entered into a telecommunications device, each number at a particular location is compared with a predetermined number. If, according to this comparison, telephone numbers which include certain digits at particular locations in the dialing sequence are entered, the telephone call is blocked. This technique may be implemented by including appropriate software into a microprocessor controlled public telephone. For public telephones which are not microprocessor controlled, a microprocessor driven system can be interposed between the public telephone and the telecommunications line. A similar algorithm can be implemented in conjunction with a PBX system. When a PBX system is being accessed from a public telephone in order to establish a telephone call using the PBX outgoing lines, the telephone numbers which are entered into the PBX can be compared with predetermined number sequences in the manner described above. A warning signal can be generated or the call can be blocked if particular dialing sequences are entered. Velocity checking can also be implemented on any of the above systems in order to detect potentially fraudulent telephone calls.

Loading the Abstract Image...

First Claim