A telephone station interface is provided with apparatus for detecting
when a called party has or is attempting to patch or bridge one telephone
call with another telephone call. The detecting of such bridging or
conferencing is accomplished through the detection of tones which are
commonly associated with such activities, such as a ring signal, a busy
signal, special information tones (SIT tones), dual tone multi-frequency
(DTMF) tones or so-called Touch Tones, call progress tones, or other
tones that occur when calls are placed. The present invention does not
have the capability of sensing clicks, pops, or other audio signals
associated with the conferencing of multiple communications circuits. The
method and apparatus herein are for managing institutional telephone
activity, and utilize a computer control unit to control a trunk
management unit, which connects institutional telephones to outside
telephone lines.