cybern0id

SIM Card Management Over GSM Modem

A small guide on how to send and receive USSD codes on Linux

I am using the built in GSM (UMTS) modem of my Thinkpad X1 extensively because I am often in places with flaky internet connections. I connect through the standard Network Manager on Ubuntu and everything works fine. There was one major annoyance though. Every time I wanted to top up the SIM balance or book a new package, I needed a phone to send and receive USSD codes. So I took some time to figure out how to do it from the shell. I wrote this down as a help for others and a reminder for myself. Without further ado...

First intsall gammu and picocom.

➜  ~  sudo apt-get install -y gammu picocom

	#!/bin/bash -ex
	# Builds arm64 debian packages from the rpi firmware repository kernels.
	# This runs on an arm64 host with arm64 compilation tools...
	# or with some sort of cross-compilation setup.
	# Debs are put in $workdir/build
	#
	# This will NOT work in Raspbian unless you have an arm64 compilation
	# environment setup. Has not been tested yet on
	# Raspberry Pi OS (64 bit) beta test version
	#