Okay...another update in the ongoing GSM phone module saga.
1. I tried an AT&T Wireless SIM card. Lo, and behold, it worked! Logged on the network right away. Nevermind that AT&T and Cingular are the same company now.
2. I tried an older 32K Cingular SIM card. Lo, and behold, it worked! Interestingly, it logged on and displayed "AT&T Wireless," not Cingular.
Therefore, the GSM phone module works. However, it does not seem to work with the new 64K Cingular SIM card as my brand spanking new 64K Cingular SIM card will NOT work. I haven't tried T-mobile, but I have a feeling if they have migrated to 64K cards, that it might not work.
So it appears that the GSM phone module will accept older technology and is unable to read the newer 64K card. BTW, this is not a problem isolated to Porsche. Apparently according to the Cingular salesperson I spoke with, there is a run on 32K cards that Cingular wants to phase out because the 64K card will not work with the new Treo.
Anyways...a brief review of the GSM phone module...
1. The automute of the stereo and the voice quality of the other party is very good.
2. The voice quality transmitted through the microphone (I think in the steering wheel) is very good.
3. The multifunction steering wheel does make the function of the phone much more convenient.
4. The phone is full featured and includes text messaging.
5. Handsfree operation is SOOO convenient...
I'm returning to the Cingular store tomorrow and getting a new 32K SIM card...Hopefully Cingular won't be completely phasing these out...