From Gomadic's Support Page:
How do I configure my ComCube to work with Sprint's Vision Service?
To use Sprint's Vision network, follow the directions above with the following exceptions:
User Name: <leave blank>
Password: <leave blank>
Phone Number: #777 (no area code, force to be a local call, must use your cell phone for this service)
Set the modem speed on your PDA or Laptop to be 115,200kbps instead of 19.2kbps
Make sure you phone's data-in setting is set to Serial and not USB. On the LG5350, this is done by on the main menu by selecting 8 (settings) and then 9 (setup) then 4 (data-in). This will take you to the data configuration area. Change method to RS232 and change speed to 115,200 bps.
More instructions can be found at:
http://www.gomadic.com/support.html
Hope this helps.