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Premise Wiring Tutorial
  • What is Premise Wiring?
    Premise Wiring is the cabling, connectors and accessories that are used to connect LAN (Local Area Network) and phone equipment within a commercial building.
  • How is Premise Wiring used?
    Premise Wiring is made up of vertical and horizontal cable runs from a central location throughout buildings to individual desktops.
Premise Wiring Terms
Backbone Wiring: The cabling used between telecommunication closets, entrance facilities, equipment rooms, or buildings.
Category 5E/6: The standard unshielded twisted pair cabling used for LAN drops.
Conduit: Circular raceway that cable is run inside. Conduit requirements are specified under appropriate electrical code.
Cross Connect: The connection method used between permanent cabling (inside the walls) and equipment. A patch cord is often used as the connection means.
Demarcation Point: The point at which operational control changes (for example, where the phone company’s responsibility ends and the building owner’s begins).
Drop: Slang term used for each cabling span pulled from a telecommunications closet.
Equipment Room: The space dedicated to telecommunications equipment.
Horizontal Wiring: The span of cabling and connectors between the wiring closet and each drop. It is called horizontal because this type of wiring does not go up or down any floors of a building.
Insulation Displacement Contact (IDC): A means of terminating wires without the need of stripping down to the bare wire.
Jumper: Single twisted pairs used for cross connecting between 66, 110, or Krone blocks.

Modular Jack: The female connector used at the end of each horizontal cabling drop. Usually Modular Jacks utilize a 6 or 8 contact modular plug (on the patching side) and a 110, Krone, or other Insulation Displacement connection method (on the permanent horizontal wiring side).

Modular Plug: The male connector usually found at the end of a patch cord.
Patch Cord: A cable assembly with modular plugs on each end. Used for patching equipment to the patch panel in the equipment room and also used to connect to phones and computers at the drop.
Patch Panel: The common cross connect method used inside an equipment room. Typical Patch Panels utilize 110 or Krone connectors (on the rear) to connect to the horizontal cabling and modular jacks on the front to connect to equipment via patch cords.
Star Topology: The topology where wiring stems from one central point.
Telecommunications Closet: Enclosed space for containing telecommunications equipment, cable terminations and cross connects.
Work Area: Building space where occupants utilize telecommunications equipment.
Typical LAN Premise Wiring
Premise Wiring

Common Wiring Standards
for Data Communications
There are two common wiring standards for LAN wiring. When buying components such as jacks or patch panels, be sure to specify if EIA568A or EIA568B is needed.
Common Wiring
Typical Telecommunications Closet
Typical Telecommunications Closet
Typical Office Drop
Typical Telecommunications Closet

Cable Testing Explained
Cable testing and cable ratings often are not understood by those that purchase network grade patch cords and equipment. The type of testing performed and the frequency of that testing often is the greatest factor in determining the cost of a cable that you buy. Often, patch cords that seem to be a good value may not be, due to the usage of low quality components and minimally compliant cable. Below is an explanation of the four most common forms of testing conducted on patch cords. Each is explained for you to decide on what best fits your application and budget. L-com strives to provide a full selection of cable assemblies for all our customers. To make selection simple, we group our cables into one of three different categories to identify the type of testing done. Certified cables require a test report produced for each assembly. Qualified cables are controlled on a lot basis and do not feature an individualized test report. Rated cables feature all category rated components but only a continuity test is performed. If you need help on your project just contact one of our experts today.

Network Channel Testing
Network Channel testing is a method used to verify performance from the workstation to the hub/switch (including patch cords). Channel testing is not accurate for individual patch cords. Both installers and IT professionals conduct this type of testing to insure that the entire cable system is capable of handling network traffic. Channel testing differs from Permanent Link testing in that it includes the patch cords on both ends of the installation. Often, patch cords are overlooked as the cause of network failures.Network Channel Testing
Permanent Link Testing
Permanent Link testing is the preferred method used by installers to certify a cable installation at a customer site. This type of testing verifies the installation by measuring many factors such as cable lengths, NEXT, FEXT and Return Loss. Several certification testers exist on the market including Fluke Networks DSP4300 series products. This type of tester features a Permanent Link adapter that connects from a workstation outlet to the telecom closet outlet.

Patch Cord Certification
Patch Cord Certification is the best method to insure that the cables will meet all of TIA/EIA-568-B.2_ standards for data transmission for Ethernet. The TIA/EIA-568-B.2_ Standard covers many details and requirements for cable quality and performance. This test involves the direct connection of patch cords to a certification tester such as the Fluke Networks DSP4300 Series. The tester will check many aspects of cable performance such as continuity, NEXT, FEXT, and Return Loss. This type of tester along with software provided by Fluke Networks can produce excellent reports for those requiring certification of their cable installation.
Patch Cord Certification Testing
Continuity Testing

Continuity Testing is the most basic form of testing conducted on cables. These types of testers look for opens, shorts or crossed connections. For Ethernet, this type of testing does not confirm network transmission capability. The most common mistake in cable pin-out is an EIA568 A to B cross. A simple continuity tester such as L-com's DXB64A can easily find this error without the expense of a certification tester.

Continuity Testing

Cable Testing Terms
NEXT: Near End Cross Talk. Signal that crosses between twisted pairs or between conductors. NEXT is measured at the transmission end (near end). Measured in dB, failures for this measurement are often caused by termination problems.
FEXT: Far End Cross Talk. Crosstalk that is measured on the conductors that are not being used for transmission at the receiver or far end of the transmission. Measured in dB, failures for this measurement are often caused by termination problems.
Propagation Delay Skew: Used to define the difference in signal speed between the fastest and slowest pair within a cable. Also can define the delay within an individual pair. Must be <45ns for a 4-pair horizontal cable.
 
Impedance: Measure of the total opposition a circuit offers to the flow of alternating current. Target impedance for UTP and STP cable is 100 Ohms. This can be affected by the twist of the conductors along with the thickness of the insulation around the conductors. Return Loss failures are often caused by cable impedance problems.
Return Loss: The ratio reflected power to inserted power. It is the measure of the signal reflections occurring along a network cable system. It is often caused by imperfections in the cable conductors, impedance mismatches, or bad contacts in a plug or jack.
  
    
 
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