Patent ID: 6760419
Filing Date: 2004-07-06
Classification: H04L

Abstract:
An integrated telephone and intercom system, comprising:a plurality of telephone stations, each station having a telephone transmitter and telephone receiver; a private branch exchange switchgear circuit tying the stations with one another and with a central office telephone line of a public telephone company, wherein the private branch exchange switchgear circuit includes a single transmit/receive communication connection; an intercom station including an intercom speaker and an intercom microphone; a telephone interface comprising an E&M tie trunk module in communication with the telephone switchgear circuit, wherein the E&M tie trunk module includes a connection for communication with the single transmit/receive communication connection of the switchgear circuit and wherein the E&M tie trunk module includes a transmit output for a voice transmit signal and a receive input for a voice receive signal, wherein the transmit output is separate from the receive input such that the E&M tie trunk module separates the transmit and receive connection of the switchgear circuit such that transmit and receive paths are not connected, wherein the E&M tie trunk module further includes a mouth signaling connection port for initiating calls from the telephone stations and an ear signaling connection port for initiating calls from the intercom station; intercom circuitry having a transmit input, a transmit output in communication with the intercom speaker, a receive output, and a receive input in communication with the intercom microphone; and an interface circuit connecting the transmit output of the E&M tie trunk module to the transmit input of the intercom circuitry over a transmit path, and separately connecting the receive input of the E&M tie trunk module to the receive output of the intercom circuitry over a separate receive path, the interface circuit comprising a signal level adjustment circuit configured to adjust audio signal levels communicated between the intercom circuitry and the E&M tie trunk module, the interface circuit further including signal isolation circuitry configured to isolate the transmit path and the receive path wherein the system provides full duplex communication between each telephone station and the intercom station.