The 300PBX-SC telephone system interface allows access from a PABX (Private Automatic Branch Exchange) to a SelecTone® system or centrally amplified paging system. A single standard RJ11 modular jack is the only input required. The 300PBX-SC is assigned a dedicated line in place of a telephone. By dialing the extension to which the 300PBX-SC is connected, direct paging access is made to the SelecTone command unit. When the connection is made, a tone is sounded both in the phone and the SelecTone® speaker amplifiers. The 300PBX-SC will automatically disconnect when the dial tone is heard or after the pre-determined time limit has expired. The Model 300PBX-SC includes both an audio output and a double-throw relay circuit to activate the music mute or other function during page. The audio output is a 600 Ohm balanced line for direct connection to an audio amplifier. A high impedance output with level adjust is also provided. The controls can adjust the Alert Tone Level, Paging Access Time, Dial Tone Sensitivity and Dial Tone Trip Time. The cadmium-plated housing can be mounted to most surfaces by means of a #6 screw through the holes in the mounting flanges. Federal Signal's 300PBX-SC Station Level Paging Adapter saves money by linking an existing phone system to a public address system or SelecTone system.