Ryan Malloy
7f82dbbbfa
The C# decompile shows enuOmniLinkConnectionType has both Network_TCP=4
and Network_UDP=3 (clsOmniLinkConnection.cs uses udpSend/tcpSend
parallel paths), and clsHAC carries an enuPreferredNetworkProtocol
{TCP, UDP} per-installation byte. User reports their panel is
configured for UDP. The TCP-only assumption was too narrow.
Wire format is identical: same Packet/Message framing, same handshake,
same per-block whitening, same opcodes, same port. Only differences:
* UDP is connectionless; each datagram = one Packet (no stream framing)
* UDP needs explicit retry-on-timeout for reliability
src/omni_pca/connection.py:
- New constructor args: transport: Literal['tcp','udp']='tcp',
udp_retry_count: int = 3
- connect()/close() branch on transport — TCP keeps the existing
asyncio.open_connection + StreamReader/Writer + reader_task path;
UDP uses asyncio.get_running_loop().create_datagram_endpoint with
remote_addr= so transport.sendto(data) works without per-datagram
addrs. The reader_task is TCP-only.
- _write_packet branches between writer.write and udp_transport.sendto
- request() loops up to (1 + udp_retry_count) attempts on UDP, retrying
on RequestTimeoutError; TCP gets a single attempt (existing behavior)
- New _OmniDatagramProtocol that decodes each datagram into a Packet
and delegates to the shared _dispatch (which already knows how to
route handshake / solicited / unsolicited)
src/omni_pca/mock_panel.py:
- serve(transport='tcp'|'udp') public arg; defaults preserve existing
TCP behavior. Internally splits into _serve_tcp / _serve_udp.
- New _MockServerDatagramProtocol that mirrors _handle_client for UDP.
Tracks one active client by addr (single-session, matches Omni's
single-client constraint). Reuses the panel's existing _dispatch_v2,
_reply_*, _build_* helpers — the dispatch logic is unchanged, only
the transport framing differs.
- New _schedule_udp_push for synthesized SystemEvents (seq=0) push
to the active client's addr after state mutations.
src/omni_pca/client.py:
- OmniClient gains transport= and udp_retry_count= kwargs that pass
through to OmniConnection. Default is 'tcp' so existing callers
are unaffected.
tests/test_e2e_udp.py — 6 e2e tests:
- handshake roundtrip
- get_system_information
- arm area with right code
- arm with wrong code -> CommandFailedError
- turn unit on -> push UnitStateChanged event
- wrong ControllerKey -> HandshakeError
All run under 0.2s. Combined with the existing TCP suite: 357 tests
pass (was 351), ruff clean across src/ tests/.
The HA integration's config_flow still defaults to TCP; users on UDP
panels can manually set transport= via the OmniClient init path. A
follow-up commit will add transport to the HA config flow as a
dropdown option.
omni-pca
Async Python client for HAI/Leviton Omni-Link II home automation panels — Omni Pro II, Omni IIe, Omni LTe, Lumina.
Includes a Home Assistant custom component (custom_components/omni_pca/).
Project home: https://git.supported.systems/warehack.ing/omni-pca Documentation: https://hai-omni-pro-ii.warehack.ing/
Status
Alpha. Built from a full reverse-engineering of HAI's PC Access 3.17 (the Windows installer/programmer app). The protocol layer captures two non-public quirks that public Omni-Link clients miss:
- Session key is not the ControllerKey. Last 5 bytes are XORed with a controller-supplied SessionID nonce.
- Per-block XOR pre-whitening before AES. First two bytes of every 16-byte block are XORed with the packet's sequence number.
The full byte-level protocol spec lives at https://hai-omni-pro-ii.warehack.ing/reference/protocol/.
Install
The library isn't on PyPI yet (pending), so install directly from the Gitea release:
# Pinned to a specific release (recommended)
pip install "omni-pca @ git+https://git.supported.systems/warehack.ing/omni-pca.git@v2026.5.10"
# Or the wheel from the release page
pip install https://git.supported.systems/warehack.ing/omni-pca/releases/download/v2026.5.10/omni_pca-2026.5.10-py3-none-any.whl
# Or with uv
uv add "omni-pca @ git+https://git.supported.systems/warehack.ing/omni-pca.git@v2026.5.10"
Once published to PyPI, the canonical install will be pip install omni-pca.
Quick start (library)
import asyncio
from omni_pca import OmniClient
async def main():
async with OmniClient(
host="192.168.1.9",
port=4369,
controller_key=bytes.fromhex("6ba7b4e9b4656de3cd7edd4c650cdb09"),
) as panel:
info = await panel.get_system_information()
print(info.model_name, info.firmware_version)
asyncio.run(main())
For the panel walkthrough — connect, list zones, react to push events — see the tutorial.
Quick start (Home Assistant)
# Manual install — works on every HA flavour
cd /path/to/your/homeassistant/config/
mkdir -p custom_components
cd custom_components
git clone https://git.supported.systems/warehack.ing/omni-pca tmp-omni
cp -r tmp-omni/custom_components/omni_pca .
rm -rf tmp-omni
Restart HA, then add the integration via Settings → Devices & Services. You'll need:
- Panel IP / hostname
- TCP port (default 4369)
- ControllerKey as 32 hex chars
Get the ControllerKey from your .pca file using the bundled CLI:
omni-pca decode-pca '/path/to/Your.pca' --field controller_key
The integration creates one HA device per panel plus typed entities for every named object on the controller: alarm_control_panel for areas, light for units, binary_sensor + switch for zones (state + bypass), climate for thermostats, sensor for analog zones and panel telemetry, button for panel macros, and event for the typed push-notification stream. See custom_components/omni_pca/README.md for the full entity + service catalog, or the HA install how-to for the step-by-step.
Without a panel — mock controller
The library ships a stateful MockPanel that emulates the controller side of the protocol over real TCP. Useful for offline development, integration tests, and demos:
from omni_pca.mock_panel import MockPanel
async with MockPanel(controller_key=...).serve(port=14369):
# Connect a real OmniClient to localhost:14369 — full handshake + AES
...
The local dev stack (dev/docker-compose.yml) packages a real Home Assistant container and the mock panel side-by-side so you can click through the integration without touching real hardware. See the dev-stack tutorial.
Tests
uv sync --group ha
uv run pytest -q
351 tests across the protocol primitives, the mock panel, the OmniClient ↔ MockPanel end-to-end roundtrip, and an in-process Home Assistant harness driving the integration via the real config flow + service calls.
Versioning
Date-based (CalVer): YYYY.M.D. Bumped on backwards-incompatible changes. See CHANGELOG.md.
License
MIT. See LICENSE.
Acknowledgments
This client is independent and not affiliated with Leviton or HAI. Protocol details derived from clean-room analysis of the publicly-distributed PC Access installer. The reverse-engineering arc is documented at https://hai-omni-pro-ii.warehack.ing/journey/.