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


To add the SMS notifications via GSM-modem integration to your Home Assistant instance, use this My button:


An SMS message can be sent by calling the notify.sms. It will send the message to all phone numbers specified in the target parameter.

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

Send message

  service: notify.sms
    message: "This is a message for you!"
    target: "+5068081-8181"

Sending SMS using GSM alphabet

Some devices (receiving or sending) do not support Unicode (the default encoding). For these you can disable Unicode:

  service: notify.sms
    message: "This is a message for you in ANSI"
    target: "+5068081-8181"
      unicode: False

Getting SMS messages

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. Sample automation that forward all SMS to user1:

Define a sensor in configuration.yaml to protect user phone number

  - sensor:
    - name: "User1 Phone Number"
      state: !secret user1_phone_number

Define a script in scripts.yaml to use the sensor

  alias: "Notify via SMS to User1"
      description: "The message content"
      example: "The light is on!"
  - service: notify.sms
      message: "{{ message }}"
      target: "{{ states('sensor.user1_phone_number') }}"
  mode: single
  icon: mdi:chat-alert

Putting it all together in automations.yaml

- alias: "Forward SMS"
  - platform: event
    event_type: sms.incoming_sms
  - service: script.notify_sms_user1
      message: |
        From: {{}}
        {{}}  mode: single

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

  • Huawei E3372h-320

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.

Note: if you have multiple USB devices, USB number order can change on boot. For this reason, it’s preferable to use your device ID and look in /dev/serial/by-id/*. For example, /dev/serial/by-id/usb-HUAWEI_MOBILE_HUAWEI_MOBILE-if00-port0.

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

More details: