I just want to add the following solutions that also work great.

You can use a function ALREADY built in the HAI controler.

1) You need to setup a serial port on the omni controler in "pro-link"

2) Here is an example of two programming blocks that would be used to arm and disarm:

WHEN HAI TRIGGER HAI1
THEN SECURITY MODE IS AWAY

WHEN HAI TRIGGER HAI2
THEN SECURITY MODE IS OFF

3) In your 3rd party processor you only have to create a serial text string "HAI1" and "HAI2".

When the Omni processor receives that "HAI1" or "HAI2" text string on any of it's serial port set in "pro-link", it will execute the automation blocks that arm or disarm.

No need to create messages as describe in my first post.

The only thing is that you need to keep track of the HAIxx command and what they do as you cannot rename these HAI triggers.

You then have 127 commands that you can send to an HAI controler from any other controler without the need to program messages.

I have tested this with a Crestron processor in rs232 and it work great. I can send triggers to control lighting, arm/disarm and do anything else in the Omni controller that had been done in HAI programming blocks.

You need to have V3.0 or higher omni version if I am not mistaken. You cannot do this in older V2.x version of omni products.

One last thing. Do NOT forget that connecting two processors together requires a crossover serial cable. The TX of one needs to go in the RX of the other one and vice-versa. Otherwhise, this will never work.