Specifications

38 | Appendix D: Cabling Guidelines
Smart Switch Software Manual
Category 5 Cable
Category 5 distributed cable that meets ANSI/EIA/TIA-568-A building wiring standards can
be a maximum of 328 feet (ft.) or 100 meters (m) in length, divided as follows:
20 ft. (6 m) between the hub and the patch panel (if used)
295 ft. (90 m) from the wiring closet to the wall outlet
10 ft. (3 m) from the wall outlet to the desktop device
The patch panel and other connecting hardware must meet the requirements for 100 Mbps
operation (Category 5). Only 0.5 inch (1.5 cm) of untwist in the wire pair is allowed at any
termination point.
Category 5 Cable Specifications
Ensure that the fiber cable is crossed over to guarantee link.
Table D-1 lists the electrical requirements of Category 5 UTP cable.
Table D-1. Electrical Requirements of Category 5 Cable
Twisted Pair Cables
For two devices to communicate, the transmitter of each device must be connected to the
receiver of the other device. The crossover function is usually implemented internally as part
of the circuitry in the device. Computers and workstation adapter cards are usually
media-dependent interface ports, called MDI or uplink ports. Most repeaters and switch ports
are configured as media-dependent interfaces with built-in crossover ports, called MDI-X or
normal ports. Auto Uplink technology automatically senses which connection, MDI or MDI-X,
is needed and makes the right connection.
Figure D-1 illustrates straight-through twisted pair cable.
SPECIFICATIONS CATEGORY 5 CABLE REQUIREMENTS
Number of pairs Four
Impedance 100 ± 15%
Mutual capacitance at 1 KHz 5.6 nF per 100 m
Maximum attenuation
(dB per 100 m, at 20° C)
at 4 MHz: 8.2
at 31 MHz: 11.7
at 100 MHz: 22.0
NEXT loss (dB minimum) at 16 MHz: 44
at 31 MHz: 39
at 100 MHz: 32