Netgear FR328S User Manual download pdf (Page 110)

FR328S ProSafe Firewall with Dial Back-Up Reference Manual v2

B-14 Networks, Routing, and Firewall Basics

M-10207-01, Reference Manual v2

Figure 8-7: Category 5 UTP Cable with Male RJ-45 Plug at Each End

Note: Flat “silver satin” telephone cable may have the same RJ-45 plug. However, using

telephone cable results in excessive collisions, causing the attached port to be partitioned or

disconnected from the network.

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 (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 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.

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Netgear FR328S User Manual Page 110