What should I do if the hotel elevator has no power GSM?

Generally speaking, the walkie-talkie has four wires, namely, positive, negative, R and L. The power supply is placed on the car roof, and the main machine is in the machine room. The car roof walkie-talkie and the car roof walkie-talkie are connected with the power supply through accompanying cables, and the main machine in the machine room is wired to the bottom pit through hoistway cables for intercom. The duty room intercom can be wired from the hoistway intercom.