I just installed the latest firmware update to my Treo 650. The install went ok, however a problem that I had before the install still persists. When I place a call (using a wired headset) the person on the other end can only hear me for about 30 seconds, then it's like the connection is dead. They can no longer hear me. If I jerk the headset out of the jack, they can again hear me for another few seconds, then it goes completely dead again. I can hear them, but they can't hear me. Any ideas? This is my second phone.

Firmware 01.31
Software Treo650-1.15-CNG
Cingular network