gregvish / gsm-matrix-gw

GSM call forwarding to Matrix. A bot that forwards calls (or SMS) from a 4G modem to a Matrix room.

GSM to Matrix Call Gateway Bot

GSM call forwarding to Matrix. A bot that forwards calls (or SMS) from a Quectel EG25 LTE modem to a Matrix room.

Required setup:

• A Quectel EG25-G based modem. For example, EG25-G USB modem from Aliexpress (Separate IPX antenna required)
  • This is the same modem module that is used on the PinePhone (https://www.pine64.org/pinephone/) and in the Librem 5 design (https://puri.sm/products/librem-5/)
  • This project uses an open source custom firmware for the modem: https://github.com/Biktorgj/pinephone_modem_sdk/ (With the EN_USBAUD feature enabled)
• Port forwarding from your public (Internet) IP to the computer that has the modem attached, and is running this project (to forward the UDP port for the VoIP calls)
• A bot account on your Matrix homeserver. You provide the creds for this bot when running this code.

Prerequisites

This uses docker, and also assumes a proper setup of the hardware on the host environment. Essentially, the following udev rules should be placed (for examle) into /etc/udev/rules.d/89-lte-modem.rules on the host machine:

ATTRS{idVendor}=="2c7c", ATTRS{idProduct}=="0125", ENV{PULSE_IGNORE}="1"
DRIVERS=="usb", KERNEL=="*cdc-wdm*", GROUP="dialout"

The Vendor and Product IDs here match the Quectel modem. This is necessary for the USB sound-card exposed by the modem to the host to be available for this software, and for permissions to be matching (dialout group, precisely). Running cat /proc/asound/cards should show something like the following with regards to the Quectel modem soundcard:

$ cat /proc/asound/cards
...
 2 [Module         ]: USB-Audio - LTE Module
                      Quectel, Incorporated LTE Module at usb-0000:00:14.0-4.1, high speed

The name of the soundcard is Module. Apart from this, the AT command port of the modem should be found, on a path like /dev/ttyUSB2, and the QMI port under /dev/cdc-wdm0. Both need to be usable by the dialout group on your host.

Building and running

./doit.sh --homeserver <YOUR-HOMESERVER> --user <BOT-USER>  --password <BOT-PASSWORD> --udp_port 49572 --modem_tty /dev/ttyUSB2 --modem_dev /dev/cdc-wdm0

The udp_port can be any UDP port that you forwarded from your router to the host machine (has to be the same port number internally and externally). This builds the docker image, and runs it as daemon that also survives reboots. The ouput can be seen using docker logs -f gsm-matrix-gw-container