With the rapid development of urbanization in recent years, the large-scale urban construction movement has promoted the continuous rise of high-rise buildings in China, and the number of elevators, one of the characteristics of cities, has been increasing year by year. Elevators have become an indispensable part of urban life and travel, and the safety of elevators has been put in the first place. A complete elevator intercom system (also known as elevator emergency rescue system) is an important part to ensure the safe operation of elevators. Once the elevator breaks down, the people trapped in the elevator can contact the central control duty room (property center) or relevant person in charge at the first time through the elevator intercom system, so as to rescue the trapped people in time and ensure the safety of every elevator passenger.

Elevator intercom system is generally divided into wired and wireless. Wired system is divided into multi-bureau wiring and intelligent bus system, wireless system is divided into GSM system, FM(FM full duplex) and digital elevator wireless intercom system. All kinds of intercom systems have their own characteristics, such as working principle, installation and wiring, and use method, but the system can meet the elevator emergency rescue function under normal working conditions. This paper compares and expounds various systems to facilitate users to choose system categories. < / p > < p > & have spent

1. The advantage of multi-bureau wiring system is that each elevator is wired separately, with low noise, reduction of decay and loud sound, simple operation of switchboard and instant communication. The disadvantages lie in its large amount of line, large amount of laying and high maintenance cost.

2. The advantage of intelligent bus intercom system is that it USES less wires than multi-bureau wiring system, the amount of work is less, and the expansion ability of single monitoring host is strong; The single extension needs to be numbered, and the fault of the single extension on the line makes the whole system unstable or even unable to be used.

3. The advantages of wireless intercom system are obvious: no expensive line cost, no high construction cost, and the cost of line maintenance is saved.

3.1 The advantage of GSM wireless intercom system lies in the use of local telephone network or mobile communication network, without the concern of line interference or signal attenuation, the call is like making a call, the call time is long and even does not set the upper limit, the disadvantage of the special duty center and the staff on duty is that the system needs to pay the GSM cartoon charge for a single extension for a long time

3.2The advantage of FM intercom system lies in the wide coverage of wireless distance, about 3 km radius. Duplex intercom, no communication costs in the later stage, the problem is that the host can only be located to the specific extension

3.3 Digital wireless intercom elevator is the most powerful functions on the market at present, the system the most stable wireless call system, maximum effective distance can reach 5 km, and can achieve telecommunication level calls effect, is the most successful make on-line version, host also can call directly to a specific each elevator, quad encryption technology strong anti-interference, without any late fees