1U rack panel with text On The Air and a keying module available under Add-ons. Often requested, Novexcomm is now offering this new optional PTT keying module for your ON THE AIR text bar. Works via the keyed PTT line from the common linear amp key line output from the rig or any source of either ground or +12 volts depending upon the equipment it is attached to. Any special plugs or connectors to the radio don't come with it; just 4 wires for keying: 2 for ground key and 2 for +12 volts key so you can hook up to 4 radios to it and they are all electrically isolated. Easy to wire and key up by PTT.