Bluetooth uses "profiles" to connect to other devices so it knows what the other devices are capable of doing. All of them have general access, local area networking, file transfer, dial-up networking, and a handful of other profiles. A Headset profile lets you use an external wireless headset to output and input audio. This is extremely useful to me because I have the Parrot CK3000 bluetooth car kit which outputs the sound from my T68i cellphone from the stereo speakers in my car so I can talk on my cellphone hands free in my car (since I have a manual transmission this is very important). If one of these bluetooth compact flash cards had a headset profile in it then I could output audio from my PocketPC to the speakers in my car so I could play all of my MP3s from my PPC wireless, or so that GPS navigation instructions could be reported over the stereo, or so that I can watch movies on my PPC with "surround sound" in my car.
But alas... no headset profiles
off to order.
[edit] NM, I don't like Ambicom's support. I think that Socket has a much better support staff and much more frequent upgrades. I'm hoping Socket will work on a headset profile because of this. I emailed Ambicom about headset profile support, I bet I'll just get the usual "it is not supported at this time."