6 categories of integrated wiring systems are still commonly used. So I studied the knowledge of 6 categories of integrated wiring systems and analyzed why 6 categories of integrated wiring systems can become mainstream technologies, I would like to share with you some notes here, hoping to help you. Why is the connection to a 6-class cabling system less likely to pass the connection test than that of a 5-class cabling system? The root cause is the uncertain impact of NEXT and round-trip losses, which is not considered in the connection test model. However, line tests designed according to the six types of Integrated Wiring System standards can produce relatively good results. Line tests do not require line connections, but test the performance of all plug-in cables. Using this test model for field testing of 6 types of cabling system cables can avoid problems like Connection Models and increase the possibility of passing tests.
One convincing argument for using the line model is that the connection model assumes that there is no connection point (CP) except for the two ends of the cable. The premise for testing the limit value calculation in this model is that, connect any end of a 90-meter-long cable, but the model also allows a CP near the end of the cable TO accommodate standard component equipment and open office design. This "extra" connection point can be 2 meters away from the TO distance. In this case, the test will bear the NEXT and round-trip losses of the two connection points, the model is built on the assumption of a connection point. In this way, in some cases, a connection point that is not considered can make a qualified connection unable to pass the test.
In addition, considering that using a permanent connection test model reduces the connection margin by 2 dB than using a basic connection test model. Draft 5th of the six generic cabling system standards uses the traditional definition of basic connections, but the definition of permanent connections was changed in draft 6th and 7th, which was achieved by moving closer to international standards. The main difference between the two models is that a cable is added between the field tester and the first connection. Permanent connections include this cable, and the basic connection does not.
This type of cable is usually non-curved, and the cables are twisted-pair shielded cables, which can minimize the winding and measurement errors. For the measurement of Category 5 cabling systems and Category 6 Cabling systems, the NEXT of the Testing cable can be considered as zero.
For the sake of convenience, the model considers that there is no CP for the measurement at the TO end of the cable. The first place that generates NEXT and the largest value is in the TO connection. Since NEXT has to flow through a two-meter-long test cable, it has been weakened before it is tested. In the Basic connection model, the signal attenuation of NEXT is normal and expected. In this way, the NEXT recorded in the test based on the basic connection model is smaller than the NEXT recorded in the, the difference is equal to NEXT's round-trip attenuation in the test cable.
However, in the permanent connection model, the measurement point changes, so that the two field testers must "Recover" the original signal amplitude at the. Currently, advanced testers can easily achieve this. Although the test cable reduces by about 2 dB NEXT, the network effect offsets this beneficial reduction. What does all this mean? Since the Model conditions have not changed, it means that when switching from draft 5th of 6 generic cabling systems to draft 6th or draft 7th (which means switching to a permanent connection model ), it will be 2 dB lower than the test with the basic connection (in high frequency band ). Considering that there is so little margin at the beginning, this will undoubtedly make the subsequent tests worse.
Details about NEXT
TIA's test model assumes that all the NEXT operations are produced by the NEXT coupling, but this is not the case. Remote crosstalk (FEXT) is divided into two reflection measurement points due to the round-trip loss effect. The FEXT reflected back may be the main source of NEXT with uncertainty (but does exist, but it depends on the characteristics of the connector, the distance between the cable and the reflection. Although this crosstalk source does exist and cannot be ignored, it is not taken into account in the TIA model.
As mentioned above, the TIA model assumes that the NEXT coupling only comes from different NEXT coupling. If a connection element cannot be well balanced, a crosstalk conversion "normal to different modes" will be generated, as shown in the NEXT with an uncertain (but indeed exists) attached to the measurement port. This is the second crosstalk source ignored by the TIA model.
The above is the motive for testing the connection of 6 types of Integrated cabling systems using the line testing method. In addition, the interoperability of connector components reduces the connection performance, which is also a reason for using line testing. As we all know, six types of integrated wiring systems have not yet achieved full interoperability. Although everything is in this direction, there are many products from different manufacturers that claim to be 6th class plugs and sockets, but once connected together, the overall performance can only reach 5th class.
For permanent connection testing, the connection performance may be decreased unless the plug matches the test cable (specified by the manufacturer of the cable. Otherwise, you need to configure a multi-line adapter, but it will cause problems such as increased costs, heavy equipment, and inconvenience.
The line test model can measure more performance margin. As mentioned above, the performance margin for permanent connection testing is very small, sometimes or even negative. This is because, although all components may be products that comply with the six-class cabling system standards, the problem is that the connection model is incomplete, rather than cables or connectors. Of course, if you select line testing, most of these problems can be avoided or greatly reduced. The line configuration provides more performance margin than permanent connections, which is a major reason.
But why do we need to perform a line test instead of a permanent connection test? One reason is the line performance of the 6-Class Integrated Wiring System.
The latest draft of the six generic cabling system standards is under approval and the Commission has published it under great pressure. Even after approval, the new draft will not be significantly different from the current draft. The existence of the questions discussed here is not the focus of the debate, and the impact of these questions is the center of discussion. Moreover, connection restrictions are already in line with international standards, so do not expect any adjustments to these restrictions. It is very likely that we will deal with these limits in the future.
Therefore, if you are a user of 6 types of integrated wiring systems or an active device manufacturer, you will certainly be very interested in the line performance. Only by testing the line can you be sure that your device will run well. Because the performance of the plug-in cable varies greatly, it is very likely that it has passed the permanent connection test, but the line is faulty. The line test can assure the user to the maximum extent, and the system that passes the line test is good.
Furthermore, the quality assurance of most 6 types of integrated wiring systems is based on the line performance. If you want to check the details of the assurance, you will find that most of them are based on the line, which is also appropriate, because this is what the wiring system users need. If you guarantee the line performance, isn't it necessary to prove the line performance?
In fact, International Standards Institute has also recognized these issues and has already recommended line restrictions for testing. The latest draft of IS11801 clearly acknowledges that the permanent connection model may not reflect the performance of the six types of cabling system connections installed. This is described in Section E.3.2 of Appendix E of the draft. It said that, to some extent, when there is a third connection point (CP) on a permanent connection, the model that may be permanently connected is not suitable. In this case, the NEXT loss limit value of the line may not be suitable for performance evaluation.
If the product to be tested includes an adapter that complies with the Six-class cabling system standards, line testing is the only option. This means that the adapter must be isolated from other connections during testing and only the plug-in cables for measurement are retained. One way to achieve this is to use adaptive vector elimination technology (AVC), which can automatically eliminate NEXT and round-trip losses in any matching line connection.
In short, if you install or maintain a 6 class cabling system, line testing has many advantages:
It is more likely to pass the test;
More useful proof reports for cabling system users;
Absolutely compliant with the system guarantee content;
Low Cost (no need to attach a connection adapter );
Long-term repeatability (no need to consider whether a connection adapter is installed );
Complies with TIA and international Structured Cabling Standards.
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