@HAO The only nodeserver available for Honeywell Thermostats is for Honeywell Home. I don't believe the TH5320R does Honeywell Home so your only choice would be Z-Wave if you want to integrate into the ISY. The caveat being I'm not sure the TH5320R actually works with Z-Wave. It looks like it can hook into RedLINK but that won't help you for either the nodeserver or Z-Wave integration.
For Honeywell Home (and the nodeserver) you are basically talking one of the following thermostats:
T5 Wi-Fi
T6 Pro Wi-Fi
Lyric Round Wi-Fi
D6 Pro WI-Fi
T9 or T10 Pro
There is also a TotalConnect2 nodeserver but it does not support any thermostats just the security system. I'm not sure if the RedLINK supported thermostats can talk to Total Connect Comfort (TCC) or not. If they can then a nodeserver could potentially be built for it but one doesn't currently exist. Honeywell has talked about bringing TCC thermostats into the Honeywell Home API but as of right now that integration doesn't exist.
