TR-800-E88R - Bosch TR-800 BELT PACK RTS, A4F HEADSET JACK, E88 BAND

On/Off & Volume ControlTurns the beltpack power on and controls head set volume.Audio Channel Select ButtonAllows user to select either audio channel A or B.Bat/Overmod Light (BAT/OM)Light will flash once when unit is turned on if the battery is good. If the light stays on, battery is low. If the light does not flash, battery is dead. A normal microphone gain setting will cause the LED to flash at the beginning of most words at normal speech levels. If the gain is too high, the LED will be red during the complete word at normal speech levels.Talk LightLED is on when the talk button, SA or WTA is active.