Speech recognition method and system with improved voice-activated prompt interrupt capability

A system for providing voice-activated prompt interrupt across a communications channel using an echo canceler, the echo canceler including an adaptive filter having a predetermined tap filter length, comprising:

• a call manager, coupled to said communications channel, for detecting incoming calls from said communications channel;
• an application interface, coupled to said call manager and responsive to said incoming calls, for generating an outgoing prompt message;
• a play task, coupled to said application interface and to said communications channel, for transmitting outgoing signals representing said outgoing prompt message through the communications channel;
• a first buffer;
• a buffer controller, coupled to said communications channel, to said first buffer and to said play task, for receiving said outgoing signals from said play task and storing said outgoing signals to said first buffer and for receiving incoming signals from said communications channel during said transmitting of said outgoing signals and storing said incoming signals to a second buffer, said incoming signals including an echo of said outgoing prompt message;
• a delay finder, coupled to said second buffer, for determining a first buffer offset signal in response to determining whether energy of said outgoing signals exceeds a first predetermined threshold;
• said delay finder further operable to determine a second buffer offset signal in response to correlating said outgoing signals in said first buffer with said incoming signals in said second buffer in accordance with said first buffer offset signal;
• said delay finder further operable to determine a channel delay in response to said first buffer offset and said second buffer offset;
• a third buffer;
• an echo canceler, coupled to said second buffer and to said third buffer, for removing said echo from a portion of said incoming signals to provide enhanced incoming signals and for storing said enhanced incoming signals to said third buffer, said portion of said incoming signals determined by said delay finder in accordance with said channel delay and said predetermined tap filter length.