Reference Manual for the 108 Mbps Wireless Firewall Router WGT624 v3
B-12 Network, Routing, Firewall, and Basics
202-10090-01, April 2005
Category 5 Cable Quality
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.
A twisted pair Ethernet network operating at 10 Mbits/second (10BASE-T) will often tolerate low
quality cables, but at 100 Mbits/second (10BASE-Tx) the cable must be rated as Category 5, or
Cat 5, by the Electronic Industry Association (EIA). This rating will be printed on the cable jacket.
A Category 5 cable will meet specified requirements regarding loss and crosstalk. In addition,
there are restrictions on maximum cable length for both 10 and 100 Mbits/second networks.
Inside 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 B-1 illustrates straight-through twisted pair cable.
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