RTU Open  1 
 
What is the RTU Open controller? 
The RTU Open controller is available as an integrated component of a Carrier rooftop unit, or as a field-
installed retrofit product. Its internal application programming provides optimum rooftop performance and 
energy efficiency. RTU Open enables the unit to run in 100% stand-alone control mode or it can communicate 
to the Building Automation System (BAS). 
On board DIP switches allow you to select the baud rate and choose one of the following protocols:  
•  BACnet  
•  Modbus  
•  Johnson N2 
•  LonWorks  
Carrier’s diagnostic display tools such as BACview
6
 Handheld or Virtual BACview can be used with the RTU 
Open controller via the 
J12 Access Port. See illustration on the following page.