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Different types of links
EN 50173 and ISO/IEC 11801 recognize different link types. Read on to learn about the different types and how to test them.
EN 50173 and ISO/IEC 11801 recognize the following link types (configurations are recognized by EN 50173 only):
- Permanent link (PL) is the part of the cabling that is installed permanently in the building. It typically consists of patch panel, horizontal cable and outlet including the connections on both ends. The permanent link may or may not contain a consolidation point (CP).
The standards‘ term for PL without a CP is configuration B, for a PL with a CP it’s configuration C. - When distributors are connected, the link patch panel – horizontal cable – patch panel is also called permanent link or configuration A.
- In case there is a consolidation point, the link patch panel – horizontal cable – consolidation point including the connectors on both ends is called consolidation point link (CP link) or configuration D.
- The channel (CH) is the whole cabling between two devices. In most cases it will consist of the permanent link plus the patch cord on each end. Channels with a cross connect are rarely used in Europe but are common in the US. The very first and the very last connector (e.g. the one in the switch port and the one in the device’s network interface) are not part of the channel. Testers mind this.
Caption: Consolidation point link, permanent link and channel
Caption: Examples of the different configurations according to EN 50173-2:2018-10.
In most projects, an installer will test the permanent link as it will remain unchanged for many years. The channel is typically tested when an error occurs in the network, as the channel test will test the complete link with all its components in one go. If an installer tested the channel after installation, all of the patch cords would have to stay in place, as the channel test becomes invalid when patch cords are replaced an thus the channel is changed.
As the channel test will not test the very first and the very last connection, it is not a good idea to use the channel test for testing patch cords. In such a case, the tester will test the cable only. The plugs and how well they are mounted on the cable are not tested. When it comes to patch cord testing, patch cord test adapters have to be used and the appropriate patch cord test program has to be selected.
The next episode focuses on different links with two, three and four connectors.
