Abstract: An improved telephone interface device communicatively couples a local telephone set to an inside telephone wire which, in turn, is communicatively coupled to an outside telephone line from a central office of a telephone service provider. The interface device includes an on-hold switch, a ring detector, a tone decoder, and a coupling switch, all of which are coupled to the bridge via an internal signal line and a control computer. The touch tone decoder receives input tone sequences from the bridge, decodes the tone sequence, and outputs a bit signal to the control computer. The on-hold switch is responsive to a command from the control computer, and is operative to maintain the signal line at a first predetermined voltage. The coupling switch communicatively couples the signal line to a node line. When the node line is coupled to the signal line, a user at the local telephone set may communicate with another user in the home, or with an outside user.