n A Single System: Today’s structured cabling is a single cabling system (copper or fiber), which covers the whole building for all voice and data (including CCTV and video) requirements. A structured cabling system consists of outlets, which provide the user with an RJ45 extension. The outlets are either one or two RJ45 connectors mounted in a standard single gang face plate, or as single snap in modules which can be fitted into floor boxes, single gang face plates (up to two modules) or dual gang face plates (up to four modules). The system enables each user outlet to be cabled back to a hub using an individual cable of four twisted pairs of copper. The cable can be Unshielded Twisted Pair (UTP) or Shielded Twisted Pair (STP), or Foiled Twisted Pair (FTP). And the cable is connected to the back of the user outlet by means of an Insulation Displacement Connection (IDC) connector. In India, it is generally the UTP.

Parameters: The most important point about structured cabling is that every vendor has to conform to the parameters specified by the Standards Committees like TIA/EIA or ISO. These standards tell you the performance parameters like how a set cabling system should be and comply with and how the individual components on the system should measure. The parameters involve: attenuation, pair-to-pair NEXT, PowerSum NEXT, ELFEXT, Powersum ELFEXT, Return Loss, Delay Skew, pair-to-pair ACR, and PowerSum ACR. Though all the words are technical jargons, in short they mean the noise levels rating, the resistance and data loss as a consequence, etc.

Cable Management: While cables have a very consistent geometry throughout their length, its when the signal transitions from a cable to a connector that a potential for discontinuity exists. The use of the cable manager provides better control over the placement of the wire pairs and automatically resolves the important issue of keeping the unsheathed wire pairs as short as possible up to the 45-degree IDC terminals.

Impedance Matching: Impedance defines the best "path" for data to traverse. For instance, if the signal is transmitting at an impedance of 100 Ohms, it is important that the structured cabling also possess an impedance of 100 Ohms. Any deviation from this set point will result in part of the signal being reflected back towards the source of data. Impedance variations can occur for many reasons. One is from the manufacturing process itself. Any deviation of conductor-to-conductor spacing or insulation properties will cause impedance to vary. Another way in which impedance can vary is by mismatched components. In fact the new Category 6 standard has taken this on board and has brought down the impedance level from + or - 15 percent for Category 5E to +or- 6 percent for Category 6.

n Technology on Copper: Today one hears mostly about Category 5 Enhanced (Category 5E), Category 6, and Category 7 solutions. Not going into much detail to what each Category of systems indicate, it must be mentioned that Category 6 is a ratified standard today. Prior to June 2002, it was Category 5E that was a ratified standard, while Category 6 was a draft standard. The other standard, we hear is the Category 7 standard, which is still an ISO development, and not yet considered by TIA. Though innovations in Copper cabling are relatively few, there are differentiated products like bonded pair cable solutions that promise significantly higher levels of post installation performance.

Category 6 is a full duplex Ethernet Physical Layer specification for 1000 Mb/s operating over Category 6 Balanced Twisted Pair Cabling (1000 Base-TX.). This means additional performance parameters for rejection of noise, increased performance criteria for common parameters like channel attenuation and return loss, and extended bandwidth from the Category 5.

The general difference between Category 5E and Category 6 is in the transmission performance and extension of the available bandwidth from 100 MHz for Category 5E to 250 MHz for Category 6. This includes better insertion loss, Near End Cross Talk (NEXT), return loss, and Equal Level Far End Cross Talk (ELFEXT). These improvements provide a higher signal-to-noise ratio, allowing higher reliability for current applications and higher data rates for future applications. Ideally suited to high performance applications such as gigabit Ethernet, Category 6 has some significant advantages over and above Category 5E cabling infrastructure. Full characterization to 250 MHz provides for two and a half times the usable bandwidth of Category 5E systems.

There is already an increased talk about Category 7. This is an ISO development only, not even considered by TIA. It is proposed ISO 11801 Class F and addresses bandwidth up to 600 MHz. Category 8/Class G is again proposed ISO draft.

This is seen as "Broadband Premises Cabling" for 1 to 2 GHz. However, the proposed channel length would be contained to 50 m. Now that the Category 6 has so much more and that there are simultaneous developments happening in fiber too, experts advise not to bother even beyond Category 6.

n Technology on Fiber: Two general types of fiber have emerged to meet user requirement: multimode and single mode. Single mode fibers can propagate only the fundamental mode. Multimode fibers can propagate hundreds of modes. However, the classification of an optical fiber depends on more than the number of modes that a fiber can propagate. An optical fiber’s refractive index profile and core size further distinguish single mode and multimode fibers. The refractive index profile describes the value of refractive index as a function of radial distance at any fiber diameter. The standard core sizes for multimode step-index fibers are 50µm and 100µm. The standard core sizes for multimode graded-index fibers are 50µm, 62.5µm, 85µm, and 100µm. Standard core sizes for single mode fibers are between 8µm and 10µm. In most cases, the material used in the preparation of optical fibers is high-quality glass.