Triggering an old Humantechnik LISA system from HA without modifying it

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I wanted Home Assistant to be able to trigger my existing Humantechnik LISA setup
(flash lamps, vibration pads, etc.).

My first idea was the obvious low-effort one: stick a Zigbee Fingerbot on a LISA
call button. It probably would have worked, but the button placement is a bit
awkward and I wasn’t too happy with having a mechanical workaround there.

Then I remembered I still had an old Humantechnik A-2463-0 telephone transmitter.

That turned out to be a much nicer solution.

The A-2463-0 is meant to detect the ring voltage from an analog phone line and
turn that into a normal LISA telephone event. So instead of touching the LISA
hardware itself, I use an old SIP ATA with an FXS port to generate that analog
ring signal.

The whole path looks like this:

Home Assistant
→ HTTP REST command
→ lisa-sip-trigger
→ direct SIP INVITE over the LAN
→ Linksys/Cisco PAP2T FXS port
→ analog ring voltage
→ Humantechnik A-2463-0
→ normal LISA radio signal
→ flash lamps / vibration pads / other receivers

So: no soldering, no RF reverse engineering, no PBX, and no SIP provider account
needed for the setup I’m using.

I ended up writing a small Python service for it and put it here:

There’s also a prebuilt Docker image:

The HTTP API is deliberately tiny:

POST /alarm/start
POST /alarm/stop
GET  /status
GET  /health

/alarm/start triggers LISA immediately and keeps retriggering it while the alarm
is active.

/alarm/stop cancels any active SIP ringing attempt and prevents further
retriggering.

One limitation is on the LISA side: once the A-2463 has already sent an event,
that receiver cycle can’t be recalled. On my setup the vibration pad keeps going
for about 28 seconds, even if I stop the HTTP alarm earlier. The important part is
that no new cycle starts afterwards.

Hardware I’ve actually tested:

  • Humantechnik A-2463-0
  • Linksys/Cisco PAP2T
  • A-2463 connected directly to PHONE 2 / FXS
  • PAP2T Line 2 configured for direct, unregistered SIP calls

Other ATAs with a normal FXS port may work too, but the PAP2T is the one I’ve
tested myself.

Home Assistant only needs two REST commands, for example:

rest_command:
  lisa_alarm_start:
    url: "http://LISA_TRIGGER_HOST:18080/alarm/start"
    method: POST

  lisa_alarm_stop:
    url: "http://LISA_TRIGGER_HOST:18080/alarm/stop"
    method: POST

The repo includes the Docker Compose setup, Home Assistant example, PAP2T
configuration, troubleshooting notes, and amd64/arm64 images.

One odd thing I found while testing: the A-2463 doesn’t seem to accept a new
trigger immediately after the previous one. Separate calls after 23, 25 and 27
seconds did nothing, while 32 seconds worked reliably on my unit. So 32 seconds
is the current default retrigger interval. That’s just an observation from my
device, not an official Humantechnik timing value.

I mainly built this because the LISA system already works perfectly well here
and I didn’t want to replace it, modify it, or glue a robot finger to it just to
get Home Assistant control.

Maybe useful for someone else with one of these older systems still in use.

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