a "free" tethering question will it work with usb modem(the app)

[wldthng842]

The device has two NAI's. Basically the NAI is a fancy word for username. Sprint uses @sprintpcs.com and @modem.sprintpcs.com. The @sprint.com is what the device natively uses to access the web and is treated by sprint's billing as your unlimited package. Traditionally when you connect a device to a laptop via USB the device knows to use the @modem.sprintpcs.com username to notify the billing infrastructure that you are being tethered and to charge the account for phone as a modem usage not unlimited usage.

Basically long story short, this program is tricking the device into thinking it is not tethered even though it actually is which means the device will use the @sprint.com username (NAI) and the billing systems will not charge you for tethered data.

I would assume that any company out there would use a similar procedure to identify tethered vs. non-tethered but I have no idea for sure. The @sprint.com and @modem.sprint.com are just examples, your carrier will be different.