Technique for detecting call metering in key telephone system

摘要

A technique for determining call charges for a telephone call in a key telephone system, which when a key telephone subscriber forms a speech path with the central office line subscriber in the key telephone system, checks the call metering during the call time, thereby detecting the call charges. The technique includes: forming a speech path with a central office line receiver by the central office line incoming of a key telephone caller; initializing a metering counter upon forming the speech path; detecting metering pulses from a telephone network, and storing the counted number of metering pulses; upon completion of the telephone call, determining and outputting the call charges; and when the key telephone subscriber is in a metering display mode, displaying the call charges to the key telephone subscriber.