Abstract: Secure monitoring of a target IP telephone may be obtained simultaneously at a plurality of monitoring stations by requiring authentication to be provided by each of the monitoring stations prior to granting access permission to monitor the call. A single request generates multiple duplicate calls to a plurality of different monitoring location, each of which must be authenticated. When the monitored call arrives at each of the multiple monitoring stations a password is used to achieve authentication permission. The password is entered at each monitoring station by a touchtone keypad that generates Dual Tone Multi-frequency (DTMF) signals (e.g., each signal is a combination of two tones at different frequencies) which is sent to an IP monitoring center, which grants surveillance permission.
Type:
Grant
Filed:
August 18, 1999
Date of Patent:
December 17, 2002
Assignee:
AT&T Corp.
Inventors:
Fen-Chung Kung, Jesse Eugene Russell, Anish Sankalia, Spencer C. Wang