SMS notifications via GSM-modem

The sms integration allows having a local execution SMS notification via Gammu. This is ideal when the internet is offline or when the power goes out.

This integration provides the following platforms:

  • Notify


Adding SMS notifications via GSM-modem to your Home Assistant instance can be done via the user interface, by using this My button:

Manual configuration steps


To configure the notification service, edit your configuration.yaml file:

  - platform: sms
    name: sms_person1
    recipient: PHONE_NUMBER
  - platform: sms
    name: sms_person2
    recipient: PHONE_NUMBER

You can also receive SMS messages that are sent to the SIM card number in your device. Every time there is a message received, event: sms.incoming_sms is fired with date, phone number and text message.

To use notifications, please see the getting started with automation page.

If the integration is used with the Home Assistant Operating System, then version 3.6 or higher is required.

For installations not running on Home Assistant or Home Assistant Core using Docker, you must install gammu-dev package:

sudo apt-get install libgammu-dev

Before running for the first time, check that the system recognizes the modem by running:

ls -l /dev/*USB*

Note: When running Home Assistant, you need to install the SSH add-on.

Required Hardware

You will need a USB GSM stick modem or device like SIM800L v2 connected via USB UART.

List of modems known to work

List of modems known to NOT work

  • No known modems

List of modems that may work

Search in the Gammu database for modems with AT connection.

Huawei/ZTE modems (and similar) devices - NOT applicable for users of Home Assistant OS, Container or Supervised.

For some unknown reason, the rule that converts these modems from storage devices into serial devices may not run automatically. To work around this problem, follow the procedure below to change the modem mode and (optionally) create udev rule on a configuration USB stick for the device to switch to serial mode persistently.

  1. Install the usb_modeswitch software to switch the modem operational mode (for Debian/Ubuntu distros):
sudo apt update && sudo apt install usb-modeswitch -y
  1. Run lsusb, its output should be similar to this:
bus 000 device 001: ID 1FFF:342a
bus 001 device 005: ID 12d1:15ca   <-------- Huawei is usually 12d1
bus 000 device 002: ID 2354:5352
bus 000 device 002: ID 1232:15ca

Identify the brand for your GSM modem, copy the brand_Id and product_id (In this case brand_id = 12d1 and product_Id = 15ca)

  1. Try disabling virtual cd-rom and change work mode to “only modem”:
sudo /sbin/usb_modeswitch -X -v 12d1 -p 15ca

Re-plug the device. After this the modem correct should work without the following ‘udev’ rule.

  1. (Optional) Configure the udev rule to persist the correct modem configuration even after disconnecting it:

Set this content in file udev\10-gsm-modem.rules in the configuration USB: (Replace brand_Id and product_id for the numbers reported by lsusb)

ACTION=="add" \
, ATTRS{idVendor}=="brand_Id" \
, ATTRS{idProduct}=="product_Id" \
, RUN+="/sbin/usb_modeswitch -X -v brand_Id -p product_Id"

Here is a sample configuration file:

ACTION=="add" \
, ATTRS{idVendor}=="12d1" \
, ATTRS{idProduct}=="15ca" \
, RUN+="/sbin/usb_modeswitch -X -v 12d1 -p 15ca"

Re-plug the USB stick, reboot the device, run lsusb again. The resulting product id now should be different and the brand id should be the same. And ls -l /dev/*USB* should now report your device.

If the device is still not recognized, remove the parameter -X from the usb_modeswitch command and reboot again.

More details: