I have a digital 24 button phone on a SL2100 system that has a wireless headset adapter connecting a Plantronics headset. This is the adapter that plugs into the recessed area on the underside of the phone. There is a flashing red light on this adapter. Also, (might be unrelated?) This headset won't work unless there is a headset key programmed. User has to push button on the earpiece and the headset key. Reseating the adapter didn't help. Any thoughts? Especially on the flashing light?

Thanks
Jim