Selective ringing receiving device and method

Selective telephone ringing-signal interruption

Sensor circuit for a telephone line

Signal analyzing system

Signal transmission control apparatus

Subscriber's line closing circuit

Switched network call progress protocol analyzer

System and method for customising call alerts

System and method for detecting customer premises equipment aler

System and method for eliminating bell tap on analog telephones

System and method for enabling a caller to selectively leave a m

System and method for identifying a caller using associated...

System and method for preventing telephone line blocking by...

System and method for processing an input signal...

System and method for processing an input signal...

System and method for providing calling-party identification...

System and method for supressing pulse dialing feedback occurrin

System and method of power limiting call processing in...

Systems and methods for caller-controlled tune notification...

Systems and methods for caller-controlled tune notification...