The THS 3 has both main and talkback microphone outputs. A latching Mic On/Off switch connects signal to the main mic output. The switch is illuminated red when the mic output is live. 36 Volt phantom power is available if condenser mics are used. Onboard phantom power allows seamless switching when talkback is activated. The switch to turn phantom power on and off is recessed to avoid accidental turn off. A momentary Cough switch silences both the mic out and the talkback out when depressed. The momentary Talkback switch connects audio to the talkback output and mutes the mic out. The announcer’s microphone is sent through a preamp and line driver that deliver signal to the talkback output at line level. There is a level control for fine adjustment of the audio sent down the talkback line. The Talkback switch illuminates green when depressed. The headphone section of the THS 3 has two inputs. Each input can be assigned to left, right or both ears. Individual volume controls are provided for left and right ears, which adjust the overall level of any inputs assigned to that ear. Input signals can be either balanced mono or unbalanced stereo. A rear panel switch selects the proper mode. Both 3 pin XLR and ¼” TRS input jacks are provided for hookup flexibility. Headphones with impedances ranging from 30 to 600 Ohms can be driven to full volume. Power is supplied by a 12 VAC power adapter, model # PS12AC1A, included with the unit.