Ryan Malloy
1901d6ec87
src/omni_pca/connection.py — low-level OmniConnection
- 4-step secure-session handshake (NewSession, SecureSession)
- Per-direction monotonic seq with 0xFFFF -> 1 wraparound (skips 0)
- TCP framing: read first 16-byte block, decrypt, learn length, read rest
- Reader task dispatches solicited replies to Future, unsolicited to queue
- Custom exceptions: HandshakeError, InvalidEncryptionKeyError, ProtocolError,
RequestTimeoutError
src/omni_pca/models.py — typed response objects
- SystemInformation (with model_name lookup), SystemStatus, ZoneProperties,
UnitProperties, AreaProperties — all frozen+slots dataclasses with
.parse(payload) classmethods
src/omni_pca/client.py — high-level OmniClient
- get_system_information / get_system_status / get_object_properties
- list_{zone,unit,area}_names walks via RequestProperties rel=1
- subscribe(callback) for unsolicited messages
src/omni_pca/mock_panel.py — async TCP server emulating an Omni Pro II
- Full handshake (controller side), seedable MockState
- Implements RequestSystemInformation, RequestSystemStatus,
RequestProperties (Zone/Unit/Area, both absolute and rel=1 iteration
with EOD termination); Nak for everything else
- 'omni-pca mock-panel' CLI subcommand
tests/ — 85 passed, 1 skip (live fixture)
- 23 unit tests for connection/models/client (canned-server fixtures)
- 7 unit tests for mock panel (raw protocol drive)
- 6 e2e tests: real OmniClient over real TCP to real MockPanel,
proves handshake + AES + whitening + sequencing all agree
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/).
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.
See docs/PROTOCOL.md for the full byte-level spec.
Quick start (library)
uv add omni-pca
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_info()
print(info.model_name, info.firmware_version)
asyncio.run(main())
Quick start (Home Assistant)
Copy custom_components/omni_pca/ into your HA config/custom_components/, 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 included parser:
uvx --from omni-pca omni-pca decode-pca path/to/Your.pca --field controller_key
Without a panel — mock controller
For testing, the library ships a minimal Omni controller emulator:
from omni_pca.mock_panel import MockPanel
async with MockPanel(controller_key=...).serve(port=14369):
# connect a real OmniClient to localhost:14369 — works end-to-end
...
Versioning
Date-based (CalVer): YYYY.M.D. Bumped on backwards-incompatible changes.
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.