{"id":696,"date":"2026-05-12T11:08:27","date_gmt":"2026-05-12T19:08:27","guid":{"rendered":"https:\/\/nramkumar.org\/tech\/?p=696"},"modified":"2026-05-12T11:10:38","modified_gmt":"2026-05-12T19:10:38","slug":"home-assistant-sms-alerts-via-asterisk-and-voip-ms","status":"publish","type":"post","link":"https:\/\/nramkumar.org\/tech\/blog\/2026\/05\/12\/home-assistant-sms-alerts-via-asterisk-and-voip-ms\/","title":{"rendered":"Home Assistant SMS Alerts via Asterisk and voip.ms"},"content":{"rendered":"\n

In the previous post we setup inbound and outbound SMS routing through a LAN Asterisk server using a voip.ms SIP trunk. In this post we will make use of this functionality to allow a Home Assistant instance in the LAN to send notifications via SMS. The nice thing about this setup is that critical notifications can be sent to the device(s) even if it is outside the LAN and even outside reach of data connectivity.<\/p>\n\n\n\n

\n\n\n\n

Network Architecture<\/h2>\n\n\n\n

The architecture involves Home Assistant running a connector which connects to the Asterisk server over the Asterisk Management Interface (AMI). The dialplan on Asterisk picks up the messages and sends them over the voip.ms trunk just like any other outbound message.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\n\n\n\n

Asterisk Setup<\/h2>\n\n\n\n

Enable AMI<\/h3>\n\n\n\n

Edit \/etc\/asterisk\/manager.conf<\/code> to add:<\/p>\n\n\n\n

[general]\nenabled = yes\nport = 5038\nbindaddr = 0.0.0.0\n\n[homeassistant]\nsecret = your_ami_password\nread = originate\nwrite = originate\ndeny = 0.0.0.0\/0.0.0.0\npermit = <HA_Static_IP|HA_Subnet>\/255.255.255.255 ; replace with 255.255.255.0 for subnet (or as appropriate for your subnet)<\/code><\/pre>\n\n\n\n
Since AMI is a powerful surface, keeping it restricted to known hosts is a good idea. We configure a user (homeassistant<\/code>) with a secure password and restrict it to read = originate<\/code> and write = originate<\/code> which gives permissions to this user for channel originates. Note however that this a weak restriction as AMI is powerful and the user can circumvent this to do other actions quite likely if they wanted to.<\/p>\n\n\n\n
Reload by running asterisk -rx \"manager reload\"<\/code><\/p>\n\n\n\n
Dialplan for Home Assistant<\/h3>\n\n\n\n
We add a dedicated context for HA messages – we take the alert text and destination number as channel variables from the AMI originate action and trigger a message send over the voip.ms trunk. I created \/etc\/asterisk\/homeassistant-extensions.conf<\/code> with the following:<\/p>\n\n\n\n
[ha-sms]\nexten => _X.,1,NoOp(HA alert SMS to ${EXTEN})\n ; Message body is passed as a channel variable from AMI\n same => n,Set(MESSAGE(body)=${HA_SMS_BODY})\n same => n,Set(MESSAGE(from)=sip:<DID_Number>@asterisk.lan)\n same => n,MessageSend(pjsip:voipms\/sip:${EXTEN}@<POP Server>,sip:<DID_Number>@<POP Server>)\n same => n,Log(NOTICE, HA SMS to ${EXTEN} status: ${MESSAGE_SEND_STATUS})\n same => n,Hangup()<\/code><\/pre>\n\n\n\n
Then included it in \/etc\/asterisk\/extensions.conf<\/code> with #include homeassistant-extensions.conf<\/code><\/p>\n\n\n\n
Reload the dialplan with asterisk -rx \"dialplan reload\"<\/code>. With this dialplan setup, Home Assistant is expected to send an Originate<\/code> action with the local channel (Local\/NUMBER@ha-sms<\/code>) to the ha-sms<\/code> context. The message body is expected in the HA_SMS_BODY<\/code> variable.<\/p>\n\n\n\n
\n\n\n\n
Home Assistant Setup<\/h2>\n\n\n\n
Custom Notify Component<\/h3>\n\n\n\n
HA has some Asterisk Integrations. But in the age of AI, it is easier to just build a small, custom component for what we want. Essentially we just need to open the TCP socket, authenticate and send some text across to the Asterisk server. Create the following under your HA config directory:<\/p>\n\n\n\n
custom_components\/asterisk_sms\/
    __init__.py
    manifest.json
    notify.py<\/pre>\n\n\n\n
__init.py__<\/strong> \u2014 empty file.<\/p>\n\n\n\n
manifest.json<\/code><\/strong>:<\/p>\n\n\n\n
{
  \"domain\": \"asterisk_sms\",
  \"name\": \"Asterisk SMS\",
  \"version\": \"1.0.0\",
  \"documentation\": \"\",
  \"dependencies\": [],
  \"codeowners\": [],
  \"requirements\": []
}<\/pre>\n\n\n\n
notify.py<\/code><\/strong>:<\/p>\n\n\n\n
import socket\nimport logging\nfrom homeassistant.components.notify import BaseNotificationService, ATTR_TARGET\n\n_LOGGER = logging.getLogger(__name__)\n\nCONF_HOST     = \"host\"\nCONF_PORT     = \"port\"\nCONF_USERNAME = \"username\"\nCONF_PASSWORD = \"password\"\n\n\ndef get_service(hass, config, discovery_info=None):\n    return AsteriskSMSNotificationService(\n        host     = config.get(CONF_HOST, \"asterisk.lan\"),\n        port     = config.get(CONF_PORT, 5038),\n        username = config[CONF_USERNAME],\n        password = config[CONF_PASSWORD],\n    )\n\n\nclass AsteriskSMSNotificationService(BaseNotificationService):\n\n    def __init__(self, host, port, username, password):\n        self.host     = host\n        self.port     = port\n        self.username = username\n        self.password = password\n\n    def send_message(self, message=\"\", **kwargs):\n        targets = kwargs.get(ATTR_TARGET) or []\n        if not targets:\n            _LOGGER.error(\"asterisk_sms: no target number specified\")\n            return\n        if isinstance(targets, str):\n            targets = [targets]\n        for number in targets:\n            self._send(number, message)\n\n    def _send(self, number, message):\n        try:\n            with socket.create_connection((self.host, self.port), timeout=10) as s:\n                s.recv(1024)  # AMI banner\n\n                self._ami(s, (\n                    f\"Action: Login\\r\\n\"\n                    f\"Username: {self.username}\\r\\n\"\n                    f\"Secret: {self.password}\\r\\n\"\n                ))\n                self._ami(s, (\n                    f\"Action: Originate\\r\\n\"\n                    f\"Channel: Local\/{number}@ha-sms\\r\\n\"\n                    f\"Application: Wait\\r\\n\"\n                    f\"Data: 2\\r\\n\"\n                    f\"Variable: HA_SMS_BODY={message}\\r\\n\"\n                    f\"Async: true\\r\\n\"\n                ))\n                self._ami(s, \"Action: Logoff\\r\\n\")\n\n            _LOGGER.info(\"asterisk_sms: sent to %s\", number)\n\n        except Exception as exc:\n            _LOGGER.error(\"asterisk_sms: AMI error sending to %s: %s\", number, exc)\n\n    @staticmethod\n    def _ami(sock, action):\n        sock.sendall((action + \"\\r\\n\").encode())\n        sock.recv(4096)<\/code><\/pre>\n\n\n\n
configuration.yaml<\/code><\/h3>\n\n\n\n
notify:\n  - platform: asterisk_sms\n    name: asterisk_sms\n    host: asterisk.lan\n    port: 5038\n    username: homeassistant\n    password: your_ami_password<\/code><\/pre>\n\n\n\n
Restart Home Assistant after adding the component and configuration.<\/p>\n\n\n\n
\n\n\n\n
Testing<\/h2>\n\n\n\n
Verify AMI is listening<\/h3>\n\n\n\n
From any LAN host:<\/p>\n\n\n\n
telnet asterisk.lan 5038<\/code><\/pre>\n\n\n\n
You should see the AMI banner: Asterisk Call Manager\/X.X<\/code><\/p>\n\n\n\n
Test from HA Developer Tools<\/h3>\n\n\n\n
In Home Assistant, Go To Settings > Developer Tools > Actions<\/p>\n\n\n\n
Select notify.asterisk_sms<\/code> and fill in:<\/p>\n\n\n\n
    \n
  • Message<\/strong>: test alert<\/code><\/li>\n\n\n\n
  • Target<\/strong>: 1XXXXXXXXXX<\/code><\/li>\n<\/ul>\n\n\n\n
    Hit Perform Action<\/strong>. Watch Asterisk logs for confirmation:<\/p>\n\n\n\n
    asterisk -rvvv<\/code><\/pre>\n\n\n\n
    You should see:<\/p>\n\n\n\n
    NOTICE: HA SMS to 1XXXXXXXXXX status: SUCCESS<\/code><\/pre>\n\n\n\n
    Using in Automations<\/h3>\n\n\n\n
    action: notify.asterisk_sms\ndata:\n  message: \"Front door motion detected\"\n  target: \"1XXXXXXXXXX\"<\/code><\/pre>\n\n\n\n
    The target<\/code> field accepts a single number or a list for multi-recipient alerts.<\/p>\n","protected":false},"excerpt":{"rendered":"
    In the previous post we setup inbound and outbound SMS routing through a LAN Asterisk server using a voip.ms SIP trunk. In this post we will make use of this functionality to allow a Home Assistant instance in the LAN to send notifications via SMS. The nice thing about this setup is that critical notifications…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-696","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/posts\/696","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/comments?post=696"}],"version-history":[{"count":2,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/posts\/696\/revisions"}],"predecessor-version":[{"id":699,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/posts\/696\/revisions\/699"}],"wp:attachment":[{"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/media?parent=696"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/categories?post=696"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nramkumar.org\/tech\/wp-json\/wp\/v2\/tags?post=696"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}