I recently started my search for a smart thermostat so that I can be lazy and change my thermostat from bed and to save money on my electric bill. I started digging to learn about my HVAC unit and I own a Carrier system.
From doing my homework (Web Searching), it appears that Carrier systems are quite good and can be do advanced things like zoning and coordinating varying numbers of different units: A/C, Heaters, Heat Pumps, Humidifiers, Heat Exchanger/Recovery Units, etc.
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Carrier Infinity systems do this by connecting all the controllers on a communication bus so all the units can communicate and share information. Carrier systems use 4 wires:A, B, C & D. A & B are the Serial Communication bus and C & D are the power wires. Sounds Great, right?!?
The flip side is this communication scheme makes these systems incompatible with just about EVERY smart thermostat out there. You can switch the unit to traditional thermostat wiring, but you lose things like variable fan control and other advance feature the carrier system can perform. No Nest, No Ecobee, No Honeywell or other smart thermostat.
Carrier (Also Bryant?) offers their own Infinity system capable touch screen, smart thermostat, but that sucker is expensive. So like any penny pincher, I started looking for a used one.
I found several model numbers out there: systxccitc01-b, systxccitc01-a, systxccitw01-a, systxccitw01-b, systxccitw01-a, systxccitn01-a, systxccitn01-a. Additionally, I found modules (remember the expand-ability I mentioned above?): systxccnim01, systxccrct01, systxccrwf01, systxcc4zc01, systxccsam01, systxxxgwro1. That’s quite a bit of different stuff.
(Using lowercase model numbers because the number look weird next to it. i.e. SYSTXCCITW01)
This post is to try to de-mystify these different models and units.
Thermostat Variants
- systxccitc01 VS systxccitw01 VS systxccitn01
- systxccitc01
- Wifi capable
- Intended to join your in-home wifi
- Alternatively, connect to a special infinity access point (AP): systxxxgwro1.
- systxccitw01
- Wifi capable
- Intended only to connect to a special infinity AP: systxxxgwro1.
- Thermostat was bundled with the AP when new.
- systxccitn01
- Non-Wifi Version of the Smart Thermostat
Version A vs Version B
It appears that there is actually very little difference between version A and B of the systxccitc01, systxccitw01 and systxccitn01. Main difference seems to be:
- Version B
- Added occupancy sensing to change climate settings when you are home
- This may not work well if you have pets
- Added occupancy sensing to change climate settings when you are home
I merged the information from Carrier website about the systxccitc01-a and the systxccitc01-b into one graphic to elucidate the differences.
Click the thumbnail below:

Module Descriptions
The follow is my understanding of the various modules after a cursory examination of the various manuals. There may be some version numbers that I missed or compatibility between versions that I missed. Please refer to the manuals for each item to get more details.
- systxxxgwro1 – Dedicated Wifi Access Point for Infinity equipment
- Used to connect Infinity equipment on a separate wifi network .
- Bridge the wifi to a network via ethernet
- systxccsam01 (SAM) – System Access Module
- Allow the Infinity system to interact with a home automation system via RS-232.
- Allows remote access to an Infinity system via the Skytel Network (Paging System) in-lieu of a wifi capable thermostat.
- systxccrct01 (CAT-5-B-SAM) – Ethernet Remote Access Module
- Connects an Infinity system to network via ethernet for remote Access in-lieu of a wifi thermostat.
- Can be used in-lieu of a smart thermostat to allow a user to change climate settings remotely.
- Allow the Infinity system to interact with a home automation system via RS-232
- systxccrwf01 (WIFI-B-SAM) – Wifi Remote Access Module
- Connects an Infinity system to a network via wifi for remote access in-lieu of a wifi thermostat.
- Allow the Infinity system to interact with a home automation system via RS-232
- systxcc4zc01 (DCM) – Damper Control Module
- This model number is to control 4 zones
- (Does this mean 4 individual dampers? I am unsure)
- This controls vent dampers for zoning a house and interfaces with the infinity system to receive and act on commands.
- This model number is to control 4 zones
- systxccnim01 (NIM) – Network Interface ModuleExcerpt from the manual:
- The Network Interface Module (NIM) is used to interface the following devices to the Infinity ABCD bus so they can be controlled by the Infinity System. The following devices do not have communication ability and the NIM is required to control:
- A Heat Recovery Ventilator / Energy Recovery Ventilator (HRV/ERV) (when zoning is not applied).
- A non-communicating single-speed heat pump with Infinity furnace (dual fuel application only).
- A non-communicating two-speed outdoor unit (R-22 Series-A unit)
- The Network Interface Module (NIM) is used to interface the following devices to the Infinity ABCD bus so they can be controlled by the Infinity System. The following devices do not have communication ability and the NIM is required to control:
I hope you found this helpful and enlightening.