Direct-attach cabling method explained, demonstrated

Also known as the Single Connector Modified Permanent Link method, the termination style suits IP devices mounted high on walls or in ceilings.

May 3rd, 2012

In a white paper, video and test-result documents from an independent lab, Graybar explains the cabling-connection method known as direct attach. Briefly, with the direct-attach method, horizontal cable is terminated not to a jack that can reside in a faceplate at a user workstation, but rather, it terminates to a plug. That plug interfaces directly with whatever network device is served by the horizontal cable - hence the phrase, direct attach.

The white paper is authored by Graybar's director of emerging technology, Karl Griffith (follow him on Twitter). It explains that the method is "also known as the Single Connector Modified Permanent Link method." He further explains that the forthcoming BICSI/ANSI D005 standard covering electronic safety and security equipment, in its current draft, refers to the Single Connector Modified Permanent Link.

In discussing the practical use of direct-attach cabling, Griffith's paper explains, "Many non-user administered IP devices are mounted in places high on walls, or on or in ceilings. In these locations the typical configuration isn't practical for installation and maintenance, and there is also the risk that these individual components might not meet building codes that require plenum-rated components."

Graybar had UL test direct-attach systems with Category 5e and Category 6 cabling. Four documents related to that testing - letters stating test results and documents containing test data, for both Category 5e and Category 6 systems - are available at the "direct-attach" page on Graybar's website.

Also accessible from that page is a six-minute video in which Karl Griffith demonstrates the termination of an unshielded twisted-pair cable in the direct-attach method.

You can download the white paper authored by Karl Griffith here, and visit Graybar's Direct Attach web page here.

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