Patent ID: 6078653
Filing Date: 2000-06-20
Classification: H04M

Abstract:
A telephone line intercepting bus for music-on-hold and auto answer mode with various detection and coupling circuits comprising of a central office (CO) line ring detector and a relay switchable call hold and music interface circuit both placed at a front end of said bus after an entry connector H1, a local loop status circuit at the back end of the bus preceding the ring relay K2, two extension powering electronic hybrids switchable by a double-pole double-trip (DPDT) relay (K1) placed in the mid portion of said bus, a series telephone coupling transformer (T2) following said hybrid DPDT relay (K1) so that it is made possible, on one part, generation of user commands from the extension telephone keypads onto the intercepting bus, said commands being structured such that when the first digit (#), a command generator, is dialed, the extension sets will be disconnected and connected to the powering hybrids while the hold and music interface connects to the CO line if an external call was being attended to at the moment, and if the said (#) is not re-dialed within 100 milliseconds while a previous external call was being attended to, then the previous status resumes ensuring operation guaranteeing specific compatibility to prevent interference based on generated commands; and said automatic answer mode wherein said extension telephone sets will be left permanently on electronic off-hook while powered by the electronic hybrids, incoming CO line calls being detected and signaled through the coupling transformer (T2) by a loud tone on the speaker prior to automatic connection of the extension speakerphone(s) to the line by releasing the hybrid DPDT relay (K1) and termination of the call by the remote subscriber being detected through the loop status detector in order to re-enter a standby status of said mode of operation by tripping the hybrid relay (K1) back.