We got an NEC Dterm Cordless II phone for someone a couple of weeks ago. According to the user's guide, whenever you place a call on hold one of four buttons (F1 - F4) light up. To return to that call simply push the lit button. The phone does place the call on hold, but none of the button light up and the call can not be retrieved. Does anyone know what might be causing this? I've called NEC about it but they've been less than helpful. We have an NEAX IVS2.