Who Sets The Cabling Standards?

The main organizations responsible for developing the structured cabling standards are the TIA (Telecommunication Industry Association) and the ISO (International Organization for Standardization). They are assisted by the IEEE committees in testing and specifying the levels of performance for the different standards. When the standards are followed they insure system performance at the guaranteed levels, backward compatibility, and wide variety of equipment choices so that the systems operate at the required level of operation. These standards are generally recognized world wide and allow combination of equipment from different countries in computer systems. The standards cover requirements for copper and optical fiber cabling components, such as cables, connectors and cable assemblies, installation, and field testing, as well as administration, spaces and pathways to support the cabling.

TIA standards are generally used by North American technicians and ISO standards are mostly used in the global marketplace. Worldwide there are standards groups such as CENELEC (European Committee for Electrotechnical Standardization), CSA (Canadian Standards Association) and JSA (Japanese Standards Association). These organizations develop standards for their own locations. Their standards are usually compatible with those of the TIA and ISO.

Confusion can be caused by the terminology used by TIA and ISO Associations since the specifications are the same or very similar, but the nomenclature can be different. For example TIA refers to Cat5e whereas ISO refers to Class D standards required and are the same for example at 100 MHZ. TIA refers to Cat6, whereas ISO uses Class E for the standards at that level. Augmented Cat6 is Cat 6A for TIA and Class E(a) for ISO and Cat 7/7A for TIA versus ClassF/F(a) for ISO.

If carefully adhered to, the standards specified by TIA and ISO guarantee that the system cabling requirements will be met correctly. They include the following categories.

1. INSERTION LOSS-Decrease in signal strength down the transmission line.

2. RETURN LOSS-Measure of the signal reflections on the cable

3. NEXT (Near End Crosstalk Loss)-Loss due to signal coupling (pair to pair) between adjacent pairs at the near end of the cabling system.

4. PROPAGATION DELAY & DELAY SKEW-Propagation Delay is the time for the signal to reach the other end of the cable. Delay skew is the delay between signal arrival at the far end on the slowest cable pair and the fastest cable pair. 

5. ACR-Difference between insertion loss and NEXT (near end crosstalk loss).

6. ELFEXT- Same as NEXT but for the far end of the cabling system.

7. PSANEXT & PSAACRF- Power sum alien crosstalk at the near end & Power sum alien crosstalk at the far end.

Because the trend in present and future computer system design is the use of higher and higher date rates, the work of the standards associations is becoming more and more important to ensure correct system design.

cabling standards, TIA, ISO, cat5e, cat6