Reference Manual for Cable/DSL Wireless Router WGR614
Ethernet Cabling
Although Ethernet networks originally used thick or thin coaxial cable, most installations currently use unshielded twisted pair (UTP) cabling. The UTP cable contains eight conductors, arranged in four twisted pairs, and terminated with an RJ45 type connector. A normal
Table | UTP Ethernet cable wiring, | |||
|
|
|
| |
Pin | Wire color | Signal |
| |
|
|
|
| |
1 | Orange/White | Transmit (Tx) + |
| |
|
|
|
|
|
2 | Orange |
| Transmit (Tx) - |
|
|
|
|
| |
3 | Green/White | Receive (Rx) + |
| |
|
|
|
|
|
4 | Blue |
|
|
|
|
|
|
| |
5 | Blue/White |
|
| |
|
|
|
|
|
6 | Green |
| Receive (Rx) - |
|
|
|
|
| |
7 | Brown/White |
|
| |
|
|
|
|
|
8 | Brown |
|
|
|
|
|
|
|
|
Uplink Switches, Crossover Cables, and MDI/MDIX Switching
In the wiring table above, the concept of transmit and receive are from the perspective of the PC, which is wired as Media Dependant Interface (MDI). In this wiring, the PC transmits on pins 1 and
2.At the hub, the perspective is reversed, and the hub receives on pins 1 and 2. This wiring is referred to as Media Dependant Interface - Crossover
When connecting a PC to a PC, or a hub port to another hub port, the 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
Network, Routing, Firewall, and Basics |
