Netgear DSL Modem Internet Gateway DG814 User Manual download pdf (Page 101)

Reference Manual for the Model DG814 DSL Modem Internet Gateway

Networks and Routing Basics B-11

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 "straight-through" UTP

Ethernet cable follows the EIA568B standard wiring and pinout as described in

Table B-3.

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 Dependent 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 Dependent Interface - Crossover (MDI-X). 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 three mechanisms:

• Uplink switch

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.

Table B-3. UTP Ethernet cable wiring, straight-through

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

1 2 ... 96 97 98 99 100 101 102 103 104 105 106 ... 109 110

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Netgear DSL Modem Internet Gateway DG814 User Manual Page 101