AT command with 3g modem while it is connected

Question

I would like to query a modem using AT commands using hyperterminal while it is connected, but whenever I try to establish a hyperterm connection, it says that it is in use. I saw a similar post How can I communicate with a 3G modem via pySerial while it is connected? that has the same problem, but my system in running on windows xp, therefore i am unable to switch to a different tty.

Hence I would like to ask if there are any solutions or alternatives to query the modem. Thank you!

Answer 1

3G modems typically (always?) provides two serial interfaces that can be used for AT command communication. Those serial interfaces ends up as /dev/ttyACM0 + /dev/ttyACM1 or /dev/ttyUSB0 + /dev/ttyUSB1 on Linux, /dev/cuaU0 + /dev/cuaU1 on FreeBSD, and on windows machines they should end up as COM<N> + COM<M> for some N and M number (not necessarily next to each other).

So open the device manager and try to find the other serial interface which is not used by hyper terminal and use that one.