How to access a PCMCIA modem's serial number?

Question

A Sprint cellular modem plugs into a laptop - often the PCMCIA slot. To connect, the user opens a program called the Connection Manager. This program has a menu option to display the serial number and phone number of the modem that's currently inserted.

Does that imply that the serial/phone number of the modem could be available to other programs running on the system? (Note: let's assume this is Windows XP.)

Specifically, could a company's VPN software be configured to pass along information about which modem is being used to connect?

Finally, is there existing VPN software that already does this, or would it have to be custom-programmed?

Answer 1

Sometimes you can get the modem's serial number using the AT command set. To see this in action, go to your control panel and open up Phone and Modem Options. Select the Modems tab, select the modem you're interested in, and choose Properties.

In the modem window, select the Diagnostics tab, and press the Query Modem button.

This opens the serial port and sends a series of AT commands to gather various settings and information. You can open the serial port in your program (or a terminal program), send the AT command, and get the same information back.

You may need to check your specific modem's AT command set to find where the serial number is stored, or use a serial port spy program to see how Sprint's program does it.

I'm not aware of any VPNs that use this information, and I can think of several ways to spoof it, since communications between the modem and the computer are not cryptographically secure.

Answer 2

Open hyperterminal or make a serial port connection programatically and use Hayes AT language to talk to it. Most software also has it listed in the device properties and/or diagnostics.

AT+GSN

press enter

Answer 3

I was able to get help with a serial PCMCIA card from www.usconverters.com, they have drivers and good tech support