Patent ID: 7477614

Claim:
A switching system comprising: a first codec having a first codec connection; a first integrated services digital network (“ISDN”) having a first security level and a first ISDN line; an electromechanical relay operable in a first mode to couple the first ISDN network to the first codec and in a second mode to isolate the first codec from the first ISDN network by severing a connection between the first ISDN network and the first codec, routing the first codec connection to ground, and routing the first ISDN line to a loop back plug; a control unit coupled to the electromechanical relay, the control unit operable to develop a first direct current (“DC”) control signal placing the first electromechanical relay in the first mode; a second codec having a second codec connection; a second ISDN network having a security level different from the security level of the first ISDN network and a second ISDN line; a second electromechanical relay operable in a first mode to couple the second ISDN network to the second codec and in a second mode to isolate the second codec from the second ISDN network by severing a connection between the second ISDN network and the second codec, routing the second codec connection to ground, and routing the second ISDN line, to a loop back plug; and wherein the control unit is further coupled to the second electromechanical relay, the control unit being operable to develop a second DC control signal placing the second electromechanical relay in the first mode.