Hi All:

Trying to use an FM transmitter in the car to play streaming audio and mp3s from my Treo over the car stereo. I've tried both an iRiver AFT-100 and a Belkin TuneCast II, each powered by the cigarette lighter, and converted from the 3.5 mm to 2.5 mm plug for the Treo. Each FM transmitter works fine initially, with clear stereo audio from the Treo to the car stereo, but then, after 30 seconds, each FM transmitter shuts off (which they are designed to do when receiving no inputted signal), even though I have the Treo's volume output set as high as possible before distortion, and the volume output from the Treo through each FM transmitter is about the same as regular FM stations received on the car stereo.

Clearly, the audio output of the Treo is not satisfying the threshold of each FM transmitter for maintaining a powered-on condition. If it makes any difference, I am converting each 3.5 mm FM transmitter plug to a 2.5 mm plug for the Treo through a Verizon-branded call answer/end button that is designed for this type of application, and includes the requisite three bands on the 2.5 mm plug.

I do not believe that the FM transmitters are defective, since they both work fine with a standard portable Walkman-style radio (bypassing use of the call answer/end button with 3.5 to 2.5 mm plug conversion).

I have read on various forum postings about the impedance from the Treo's output not being sufficient to trip the mono-to-stereo sensor with headsets, such that people have either had to select different headsets or use a Seidio "Audio-Out Coupler" which resolves audio-out impedance issues. Would anyone happen to know if such an impedance adaptor is required to get an FM transmitter to work with a 700p, or about any other recommended solutions?

Thanks very much for your kind assistance...