The Direct Attach method removes the jack and patch cord from a typical Ethernet connection on the far end and attaches the device directly to a modular plug on the end of the horizontal Ethernet cable. Karl Griffith of Graybar explores the benefits of this solution.
Graybar has identified an alternative method for network connections in commercial facilities, known as Direct Attach. The typical cabling structure for voice and data in commercial applications uses two four-pair cables terminated on a patch panel in a wiring closet at the near end with a workstation outlet on the far end. The workstation outlet usually consists of a faceplate, jacks to terminate the cables, and patch cords to connect the user equipment.
The patch panel allows the building network team to administer the network, and the workstation outlet offers the building user a connection for network devices like computers and telephones. Also on the far end are non-user-administered IP facility devices such as security cameras and WiFi access points. These types of connections are relatively permanent, and in most cases, it is not practical to use a standard telecommunications jack, faceplate, and patch cord.
Graybar investigated Direct Attach. Also known as the Single Connector Modified Permanent Link method, Direct Attach removes the jack and patch cord from a typical Ethernet connection on the far end and attaches the device directly to a modular plug on the end of the horizontal Ethernet cable.
Direct Attach is also a different way of thinking about how Unshielded Twisted Pair (UTP) cables are used in buildings. High-quality, standards-based UTP cables are becoming the dominant choice for the transport of Internet Protocol (IP) systems in commercial buildings, and IP has become the leading communications transport protocol used by most building control and monitoring systems. Direct Attach was designed to help network architects and technicians leverage both their skill in communications wiring systems and UTP as the cable of choice for building facility-system networks.
The days of disparate communication sub-systems in buildings are at an end with the migration toward integrated systems communicating over IP. Today, building sub-systems are a mixture of multiple protocols, and the information provided by these various protocols can be formatted into IP packets and uniformly transported across an IP network. This allows for system control, monitoring, and analysis virtually anywhere, via the Internet.
EIA/TIA cabling standards recommend that the two four-pair cables used in building voice and data systems terminate on eight-position modular jacks. These jacks can be mounted to faceplates attached to the wall, modular furniture, or in floor boxes. The EIA/TIA standards also recommend two cable terminations in office environments – one for voice and one for data.
However, 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. Also, typically the jack, faceplate, and patch cord are not aesthetically pleasing, and the exposed patch cord can become a nuisance or safety hazard.
The Direct Attach philosophy aims to decrease the safety hazards and configuration issues encountered with non-user administrated IP devices by installing the modular plug directly on the end of the cable servicing the IP device, therefore eliminating the jack, faceplate, and patch cord.
To validate this concept, Graybar worked with the independent testing organization Underwriters Laboratories (UL) to test and validate the Direct Attach system. UL actively and passively tested category 5e and category 6 UTP cabling systems, in various configurations, to validate that the Direct Attach system complies with the applicable standards. In addition, the Direct Attach system was tested with a network traffic/packet generator to validate the cabling system would pass IP network traffic. Test results, video demonstrations, and more information are available for review on Graybar’s website.