Hardware Manual for the Model CG814WG Wireless Cable Modem Gateway
D-12 Networks, Routing, and Firewall Basics
transmit pair must be exchanged with the receive pair. This exchange is done by one of two
mechanisms. Most hubs provide an Uplink switch which will exchange the pairs on one port,
allowing that port to be connected to another hub using a normal Ethernet cable. The second
method is to use a crossover cable, which is a special cable in which the transmit and receive pairs
are exchanged at one of the two cable connectors. Crossover cables are often unmarked as such,
and must be identified by comparing the two connectors. Since the cable connectors are clear
plastic, it is easy to place them side by side and view the order of the wire colors on each. On a
straight-through cable, the color order will be the same on both connectors. On a crossover cable,
the orange and blue pairs will be exchanged from one connector to the other.
Cable Quality
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.