20Operation instructions for controllerPower supply (12V, GND): 12V DC, please pay attention to “+, -” of power supply.Fire alarm linkage contact (ALARM1, ALARM2): Short circuit the ALARM1 and ALARM2 (Reserved port).Third party interface (B1, A1): A1 — 485+, B1—485-(Reserved port).Communication port (B2, A2): It is used for connecting converter, please pay attention to “+, -”, A2—485+, B2—485-.Note: B1, A1 are unavailable to the Split Controller; B2, A2 are available.Controller InstallationThe unit can be connected to the sub controller. Only one main controller is allowed in the whole split system, and the restcontrollers are sub. If the controller is set as a sub controller, the controller can only view the unit parameters and cannotchange the unit operation status.Don’t install near devices that produce electrical interference such as AC motor, radio transmitters like network routersand consumer electronics.Other electrical noise producers could include computers, auto-door openers, elevators, or other equipment what canproduce noise.Don’t install in wet locations.It will cause failure if you install in a place that shakes violently.Don’t install in the place where it is exposed to direct sunlight or near to the heat. This will cause failure.Installation conditionFirst, attach the mounting plate to the wall. Using a job box is preferred. Use A and B holes for an 86mm box, use C andD holes for a 120mm box. Please take note of the UP indicator.Mounting control