The VAR1 Voice-Activated Relay is a DPDT relay device that is activated when an audio signal is detected at the microphone pre-amp or at 70V, 25V, or 600-ohm line level inputs. It has a number of useful applications, such as muting a sound system in response to a microphone or telephone page, activation of accessory (security) equipment, or activation of a zone paging module. A slide switch is included to select the pre-amp or the line inputs. The VOX detect circuit also includes volume, sensitivity, and delay controls. The audio output is an isolated 600-ohm transformer. The unit operates from a DC power source (not included).