We use the Nx-8E with their NX-587E Virtual keypad when we integrate security with Crestron. Very simple to integrate using SB. Basically mimics one of the GE keypads. It seems like it is a lot less taxing on the system then using the serial port on the alarm panel, so it works fine with the slower adagio processors as well.
Basically a device that has a serial port in one end and a rj11 port in the other end, that gets wired to the keypad buss on the alarm panel.

Heard to many horror stories about using Crestron with the Ademco panels, so never even tried it. Otherwise good panels though