A WIRE-BOUND TELECOMMUNICATION DEVICE AND A CIRCUIT FOR USE IN SUCH A DEVICE

摘要

In known telephone subscriber end stations a caller_ID IC detects a tone alerting signal TAS alerting that successive caller_ID information can be received for displaying on a display of the phone. The known station applies narrow frequency band filters to detect tones indicating the end of TAS. Such a detection is not flexible as it can only be used for a specific caller_ID signal protocol. A flexible detector is proposed which can easily be adapted to widely varying protocols and which can also be used for other purposes such as the detection of power drops in a FSK signal. The detector comprises means for determining a time-domain signal representing the signal energy of a signal on the subscriber line in a predetermined time interval.