I'm writing this to try and clear up some of the confusion between these two protocols, what they do and when you need which one of them.

Crestron Protocol
This protocol is used for instant Zone/Area updates being fed to the Plug-In. This is the only protocol that will feed updates back to the plug-in when an event occurs on the alarm system.

For this reason the Crestron protocol is most likely the most important protocol for you to use.


Simple Protocol
This protocol is a great protocol for sending commands to the alarm system and getting a response back. The protocol is far more enhanced than the Crestron protocol and a lot more information can be pulled back from the panel, such as voltage/current ratings etc. You can even use this protocol for sending X10 commands if your alarm panel is equippped with the X10 interface.

However, this protocol does NOT support Instant Status updates. In other words if a zone status changes the Simple protocol will not immediately send an update to the plug-in.


So, do I need two COM ports?
Well, Yes, erm and maybe No. According to Texecom once a COM port has been configured for the Crestron protocol this should now be the only protocol that works on that COM port. However, it would appear that, in some cases, the same port will still accept Simple protocol commands. However as this is unsupported by the manufacturer it may or may not work for you. Two COM ports seems to be the safer option to get the fuller set of integration.