Research seems to indicate it is unlikely to be possible to do it...
http://www.securegsm.com/pages.php?pageid=85Above is cool app too, as you should know that standard GSM is not secure !
However, changing the phone to use GSM may enable this, but at the much reduced data rate of 9.6K.
I recall reading some months ago that CSD via UMTS was enabled on the Three network, but they caught on and stopped it. I need to do some tests and find out.
Again it seems that O2 allow CSD via GSM from inclusive mins - I know as I have done this. I didn't use the WAP service on the phone as it is cr4p. It was just simply as a modem hooked up to a host pc.
This kind of comes back to some other research I have conducted on tunneling data via Skype. I wonder if it is possible to disguise a data call as a voice call and therefore use inclusive mins. I know the answer already - yes - but don't know how to do it - and the cincher is what would the date rate be. Again I think the answer is no where near as much as a genuine CSD via UMTS call. Plus there is a greater overhead on the host PC to work with raw audio from the phone and push audio back out through the phone.
Ha - it's never easy - but thats the fun of the journey !