[justlurking]

You are trying to modulate digital data into audio. Your phone then converts it back into digital data, using rules designed to handle voice. The process is reversed at the other end.

Cell systems are designed to use minimal bandwidth to transmit VOICE audio. It's not designed for the audio tones used by telephone modems.

And on top of all that, I'm not sure that your Bluetooth connection isn't trying to make a digital connection after all. And AT&T has explicitly disabled that, unless you pay for what they call "tethering".

[Desron13]

"AT&T has explicitly disabled that, unless you pay for what they call "tethering"."

That is correct. You will also need to download the free AT&T Communication Manager software from the link below.

http://www.wireless.att.com/businesscenter/solutions/wireless-laptop/software.jsp