485 bus panel, sometimes we also referred to as the bus panel. The concept of cabling is "hands-in-hand". That is, the four lines of positive, negative, A, and B of each terminal device are connected end to end, and they can be connected to the 485 communication port of the RCU host. The advantage is that wiring is saved. The disadvantage is that the cost of the terminal equipment is higher and the construction personnel are more demanding. If there is a problem with another equipment, it is difficult to find and maintain it. Unless the site can not be normal wiring reasons, in addition to air conditioning controllers and other equipment, it does not advocate the use of 485 bus switch panel.