Centralite Elegance MCP on HA LiteJet: RS232 2 at 19200 opens but no response to +, ^, or G

Third party integrations
1

I am trying to connect a Centralite Elegance MCP to Home Assistant Green using the official LiteJet integration.

Setup

  • Centralite Elegance MCP
  • RS232 2
  • 19200, 8N1, no parity
  • FTDI USB to serial adapter on HA Green
  • Tried both direct and null modem paths

What works

  • HA sees the FTDI adapter
  • serial device shows up correctly under /dev/serial/by-id
  • the MCP programming port has responded in past testing

What fails

  • official LiteJet integration times out during setup
  • logs show: “No response to ‘+’ or ‘^’ command. No LiteJet MCP connected?”
  • from HA terminal, I also tried sending +, ^, and G\r directly to the serial device and got no response
  • listening with cat while pressing physical keypads also produced no output

Other checks

  • DIP switches appear all OFF, so RS232 2 should be 19200
  • old Crestron cable continuity checks as straight through on 2, 3, and 5
  • null modem test also failed

Question
For Centralite Elegance, is there any MCP configuration required beyond baud rate for RS232 2 to answer the LiteJet protocol?
Specifically:

  • 3rd party mode enable?
  • CR after each response?
  • load/button event output enable?
  • anything special about RS232 2 versus the programming port?
2

Another update on Centralite Elegance XL + HA LiteJet (192-load mixed panel with LVRB + fan boards + 31 scenes):

Tested both RS232-2 and RS232-3 with straight-through cable at 19200 8N1.

  • Handshake no longer fails immediately on ‘+’ / ‘^’ (after enabling Third Party CR, Load Report on loads, and Spontaneous Output on inputs in Centralite programming software).
  • Timeout now occurs during entity enumeration on L (loads), M (scenes), and K (keypads/switches).

Centralite programming software reads the panel correctly (names, states, scenes, and time all correct).

This looks like a compatibility issue with the LiteJet / pylitejet library on a full-size Elegance XL system.

Has anyone successfully run the native LiteJet integration on a full Elegance XL system?
Or is the way forward a patched pylitejet / custom component (for example, the older kohai-ut fork or similar)?

Thanks!

3

New diagnostic clue from HA LiteJet integration:

Diagnostics show the built in integration is loading pylitejet 0.6.3 and is modeling my system as:

  • model = LiteJet
  • loads = 1 to 40
  • button_switches = 1 to 96
  • scenes = 1 to 41

But the actual Centralite Elegance XL panel, confirmed by Centralite software, is:

  • 192 load slots
  • 31 scenes
  • mixed hardware including LVRB and Fan Speed Control boards

So HA appears to be using fixed LiteJet sized ranges that do not match the real Elegance XL system.

This seems like a very strong clue for why enumeration fails on L, M, and K even though the Centralite software can read the panel correctly.

4

I have no experience with your tech stack.

However if you are building your own integration for anything that talks RS-232 I would recommend checking out RemSerial. Its just a small C program that handles the serial communication and exposes a TCP socket.

I switched over to it for two reasons:

  • I got fed up trying to deal with serial communication.
  • I can leave the device plugged in to one machine and if I want to debug from a different machine, I can just put the hostname into my editor/debugger and send commands over the network.

TL;DR - its basically becomes a “Network Attached Serial Port”.