How to unlock USB broadband modem on Linux

Hello, in this article i will uncover the basic concept of how to sim-unlock the USB Broadband modems from GNU/Linux operating system using basic tools. We will test Huawei E3131 Modem and will use this public page to get the unlock code for free.

Preparations:

apt-get install minicom
minicom -s

This opens up minicom in the configuration mode. Set the Serial Port so select Serial Port Config from the list of options and press Enter.
First thing is to change the port to /dev/ttyUSB0. So press A and change the /dev/tty0 to /dev/ttyUSB0 And press Enter. Next, we need to change the Baud Rate, paritiy and bits to 9600,N,8 (respectively). To do this, press E. From the list of options C has 9600, so press C Press Enter to confirm. now it should look like this:

A – Serial Device: /dev/ttyUSB0
E – Bps/Par/Bits: 9600 8N1

Press Enter to complete the Serial port Setup. Now select Exit to exit the configuration menu. Note, this is Exit and NOT Exit from minicom option. Now it’ll initialize the modem. Now comes the actual command to unlock the dongle. The terminal you’re in now is not a interactive shell like the usual command prompt. You cannot make any mistakes in typing commands here. the AT command to unlock the dongle has to be entered in capital letters so its a good idea to press capslock.

AT^CARDLOCK="xxxxxxx"

Replace xxxxxxx with the unlock code (NEW ALGO CODE) for your dongle, the "" are necessary! If everything worked, you should get the answer OK.