Aiphone Corporation GT-1A. The GT-1A is an audio only tenant station for the GT series Multi-Unit entry system. It is equipped with a talk, door release, and optional service button. When a visitor calls, the tenant station rings and is answered by one touch of the talk button. The GT-1A also has the capability of calling the Concierge/Security Guard station(s), turning on a light while speaking with a visitor at the entrance, receiving an emergency tone from a pull cord or panic call button, and releasing a door. The GT-1A is designed to be surface mounted, and has a slim streamlined design. Up to four GT-1A units can be used in the same tenant location. Communication is hands-free at the entrance station when a tenant answers the call, and is either VOX hands-free or push-to-talk at the tenant station when speaking with the visitor.