In recent years, with the rapid progress of science and technology, the information industry has also been booming, and wire and cable is the blood vessel of the industry, so the demand for wire and cable products is also increasing. In fact, new wire and cable products have indeed sprung up, showing their skills in various emerging high-tech industries, such as communication cables, security cables, and fire cables.
It is reported that the annual growth rate of the cable market is about 8%-12%, of which the growth rate of the security cable is particularly eye-catching, although China's security cable industry has some problems, such as late start, backward technology and equipment, but its growth rate can be maintained between 15%-20% per year. After more than 30 years of vigorous development of China's security industry, there are more and more industry segments, and the scope of application is increasing. Among them, the security cable in the access control system is also a part that cannot be ignored.
In the building video intercom system, the quality requirements for connecting cables are quite high. The cables for transmitting voice signals and alarm signals mainly use more than 4-core polyvinyl chloride sheathed flexible cords (RVV), and coaxial SYV-75-5 are mainly used for video transmission. Nowadays, there are also some new technologies for signal transmission including video transmission through network twisted wires, without coaxial lines. If the system is to prevent external interference or grounding, the connecting wire used in the system must be shielded wire (RVVP) type shielded cable.
rs-232-c is a serial physical interface standard developed by the electronics industry association eia(electronicindustryassociation). Rs is the abbreviation of "recommend standard" in English, 232 is the identification number, and c represents the number of modifications. The rs-232-c bus standard has 25 signal lines, including a main channel and an auxiliary channel. In most cases, the main channel is mainly used. For general duplex communication, only a few signal lines can be realized, such as a sending line, a receiving line and a ground line. rs-232-c standards specify data transfer rates of 50, 75, 100, 150, 300, 600, 1200, 2400, 4800, 9600, 19200 baud per second. The rs-232-c standard stipulates that the driver is allowed to have a 2500pf capacitive load, and the communication distance will be limited by this capacitance. For example, when a 150pf/m communication cable is used, the maximum communication distance is 15m; If the capacitance of the cable per meter is reduced, the communication distance can be increased. Another reason for the short transmission distance is that the rs-232 belongs to single-ended signal transmission, which has problems such as common ground noise and inability to suppress common mode interference. Therefore, it is generally used for communication within 20m.
With the rapid development of my country's national economy and information technology, foreign-funded enterprises have taken a fancy to China's huge cable market and have continued to pour into the country. In addition, domestic people are paying more and more attention to security. I believe that domestic security cables will usher in The peak period of development
