Tele-Communication, Inc. BUSYLIGHT-COMBI: Cell Phone ™ Wired ™ Headsets Power Protection / Security > Alarms Sirens > PLENOM Alarms Sirens PLENOM BUSYLIGHT-COMBI Busylight for Desk Phones and Headsets, Audible/Visual Busylight Combi is for everyone who needs to concentrate at work without being interrupted. Busylight automatically lights up red when you are occupied on your headset, and it can light up in a blue colour when you need to work uninterrupted. In that way Busylight is both a headset indicator/lamp and an option to "shut the door" in the open plan offices.