To connect four lines. First of all, the control line, generally for the implementation of the terminal 1, 2 I control Zhang, connected to the DC24V power supply, it is action (smoke vent open); and then is the signal return line, generally 4, 5, 6 for a group of passive signal return microswitch, 5 is a public **** point, and then according to the requirements of the signal return to pick 4 or 6. there are a variety of types, there is a kind of actuator with the same actuator, the connection is also the same. The same, there are some ordinary fire damper, it does not have a control line, it is connected to the signal return on the line, there are automatic fire damper, it is in addition to the action control, there is reset control, there is also a signal return. I hope to be able to help you, in fact, the general actuator junction box cover has a wiring diagram, you look at it to understand.