In the actual comprehensive wiring project, in order to save the material cost and installation cost, some customers do not use the copper cable distribution frame at all in the weak power room of the management subsystem, but directly use the horizontal cable pressure crystal head, and then insert the equipment. The result is that the project can not be checked and accepted. What is more serious is that the size of the crystal head spring is not standard due to the uneven mixing of the construction personnel and the unstable quality of the pressed crystal head. The port of the device is plugged in. Thus it can be seen that the copper distribution frame is very important in the wiring system engineering.
According to the ANSI/TIA 568murC standard, the distribution frame means “Patch Panel”.
The distribution frame is the most important component in the management subsystem, and it is the hub component to realize the connection conversion between the vertical trunk and horizontal wiring subsystems.
According to the installation location, the distribution frame can be divided into rack type and wall-mounted type; according to the different types of transmission media, the distribution frame can be divided into copper cable distribution frame and optical fiber distribution frame, in which copper cable distribution frame can be divided into UTP, FTP, coaxial cable, audio and video distribution frame, etc.; according to the different structure, it is divided into modular type and integrated type; according to the place of use, it is divided into general distribution frame and intermediate distribution frame, and so on. All said, the distribution frame is not only the most familiar part of the network wiring system, but also the most easily mistaken part.
The most commonly used type of distribution frame: rack-type copper distribution frame.
The rack type is our most common distribution frame installed on the standard 19-inch cabinet, and the copper distribution frame is used in copper cable links, such as Category 6A, Category 6, Super Category 5 copper systems, and so on.
Size and structure
Because it is used on standard 19-inch cabinets, there are two key terms for wiring frames: “19 inches” and “U”. 482.6mm means that the panel length of the device is 19 inches, so the length of the distribution frame is generally 19 inches (inch).
“U” is a unit that represents the external size of the server, which is the abbreviation of Unit, 1U=44.45mm=1.75 inch (1 inch = 2.54cm). It is also the international standard of server size stipulated in IEC297 series standards. There are clear U marks on the front and rear posts of the cabinet to facilitate the installation of equipment.
Because the rack distribution frame is also assembled on a 19-inch cabinet and has to follow this size, when we describe the height of the rack distribution frame, we usually use “U” to describe it, such as 1U, 2U, etc.
As can be seen from the above two pictures, the four key installation dimensions of the two distribution frames are the same.
Figure 1: 1U24 port shielding modular distribution frame
Figure 2:1U24 port modular unshielded distribution frame (category 6)
Hole position analysis
Figure 3 shows the hole bitmap of a rack, and the two dimensions in the red box on the diagram are the dimensions that match the distribution frame, so the four mounting holes of the distribution frame are also manufactured strictly according to the dimensions shown above.
Perhaps careful friends will find that if you take a closer look, the actual hole bitmap in figure 4 looks inconsistent with that in figure 3. In fact, there are many holes, but there are very few holes in figure 3.
Picture 3: excerpt from: GB/T 19520-1 (IEC60297-1)
Picture 4: actual cabinet hole bitmap
Integrated distribution frame
After introducing the key installation dimensions of the distribution frame, let’s talk about the selection of the distribution frame: modular or integrated.
|Modular distribution frame||Integrated distribution frame|
|Structure||Combined type: two independent products constitute a common distribution frame installation frame + information module||All-in-one: an independent product. Distribution frame installation backplane + PC Assembly + tail Card Terminal + RJ45 socket|
|Feature||With the same installation frame, different types of wiring frames can be realized according to different modules. For example: 1024 non-screen knock type 6 modular distribution frame, use 1 installation frame + 24 category 6 unshielded modules. By the same token, 24 super Category 5 modules will become a super Category 5 modular distribution frame with non-screen top of the 1U24 port.||Each category of distribution frame is a separate product, and the category must be marked separately on the product, such as super category 5, category 6, category 6A, etc.|
|Overall||Flexible configuration, no waste of ports, convenient operation and maintenance, advantages of comprehensive cost||The configuration is not flexible, the port may be wasted, the operation and maintenance is slightly poor, the individual product has a slight advantage, and the comprehensive cost does not necessarily have an advantage.|
Picture 5: 1U24 port integrated unshielded distribution frame (Category 6)
The use of product
After introducing the key installation dimensions of the distribution frame, let’s talk about the use of the distribution frame, according to the standard requirements, in the permanent link, both ends of the link must be end, and then use jumpers to connect the equipment.
In practice, the end-to-end usually refers to one end-to-end information module and the other end-to-end distribution frame (if a modular distribution frame is used, it is first connected to the module, and then the module is assembled on the modular distribution frame), as shown in figure 7 below:
Fluke90 meter permanent link test
When the cabling system project is completed, a rigorous permanent link test will be carried out according to the above model.
Nonstandard design and construction
It can be seen that if we do not design and construct according to the specifications, it is impossible to make a wiring system that meets the standards. in the actual project, in order to save the cost at this end of the distribution frame, we will directly do so in the above way. no wiring frame, no original factory jumper, of course, save the cost, press the crystal head with wire pressing clamp, and then plug in the equipment directly.
This is extremely harmful, mainly reflected in the following aspects:
- Unable to accept the test according to the standard.
- The size of the 8PIN contact spring on the crystal head can not be guaranteed, which affects the transmission performance.
- As the size of the contact part of the crystal head cannot be guaranteed, there is a great risk that the equipment will be broken.
In a project, we should understand is cost of the equipment will be more if the importance of wiring frame is ignored.