How to choose the network line for security monitoring?

Release time：2018-2-8  Times of browsing：454

There will still be many problems in the construction process of security monitoring, can not pass the acceptance, the greatest possibility of a bad situation is that the "selection of wire" and "selection of equipment" these two gates can not be secured, by contrast, the most difficult is the selection of wire unqualified. Because if the quality of the twisted pair transmission is not good, the construction personnel can still return the goods by various means, and re-select other brands of good quality products; and the selection of unqualified wire is far from "return" and "re-election" so simple, it is likely to lead to the whole project must be re-wiring, waves It costs a lot of manpower and material resources to cause fatal damage to the project. Therefore, we must attach great importance to the "wire selection" this link, must not allow inferior wire into the project.

There are many classifications of twisted-pair cable, basically we recommend that you choose the unshielded category 5, super-Category 5 cable can be used to transmit VGA video can be used to select six types of twisted-pair cable. According to the test results and experience and cost-effective, super 5 lines are the best. So how do we choose this "high quality" super five line?

According to the experience of our customers and friends, inferior wire rods are mainly manifested in several aspects. First, the outer layer is wrapped loosely, not closely, high-quality wire rods can often see the lines of wire rods. Second, the blue, white and blue, green, white and green, orange, white orange, brown, white brown four colors of inferior wire are not natural, and some white line without marking color, which are not standardized. Third, there are two pairs of good quality wire, the other two pairs of wire is copper-clad iron, poor quality, is used by black-core manufacturers to recharge the number of excessive, four pairs of wire resistance value difference is too big. Because of the different stranding degree of twisted pair, there will be some difference in the length of the four pairs of wire, which leads to the difference in the resistance value of the four pairs of wire, but the difference is very small, if the difference is too large, such as greater than 5 ohms, it will cause a high degree of attention. The method of testing is: first, each pair of twisted pair wires is connected in series at one end (short circuit), and the resistance of the whole loop of the twisted pair wires is tested from the other end. The resistance of the whole loop of the twisted pair wires is recorded along the way. After testing, the resistance difference of the four pairs of wires is compared, such as the first pair is 56, 56.3, 56.8, 56.6 values are closer. Less than 5 ohms, which shows that the difference of wire rod is relatively small, and the wire quality is relatively average. If it is 56, 56.9, 150, 160.5 this type of wire is certainly inferior, this line may be used in the network, because we generally use only two pairs of lines in the network, the rest of the line used as a spare line, often empty and useless, but used in our security monitoring project to transmit video images. Absolutely not. Because we use a pair of lines to transmit a signal, this line will lead to the situation is part of the line image is very normal, but the other part of the image is not out, out is also black and white, a lot of scratches, there is no way to debug a clear image, this line 10 meters can not go through the image.