depends on what purpose you have in faxing through your cell phone. If you simply dont have a landline... using a data cable, your phone will show up as a modem in windows, but i have never tried to use it as a fax device, only for internet
if you just need it to fax long distance, heres what I do
1. set the destination number into your phone book, i prefer setting it to "1" for quick access
2. prepare your fax, and direct your fax machine, or computer to fax to your cell phone number.
3. when the cell phone rings, answer, but immediately enable your microphone mute
this part may be different depending on your model, check your manual, or ask someone else who is more familiar with your phone(
4. select "contacts" soft button
5. select the fax number you set and press send...if you followed my lead, this should be quick
)
6. once connected to the destination, hit send again, this should (read above) connect you with a 3-way (conference) call. with the mute on, essentially this means that you have routed your own phone call
the two fax machines should be able to correct any errors caused by the audio compression of cell phones, atleast i have never had a problem on alltel
additionally, my phone does say something about faxes in its menu, but i have never been able to figure out how to use the fax features.