Model DS309 Dual Speed Hub Installation Guide

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. Most ports on hubs and repeaters have media-dependent interfaces with

crossover ports. These ports are referred to as MDI-X or normal ports. Computer and workstation

adapter cards are usually media-dependent interface ports referred to as MDI or uplink ports.

These two figures illustrate the use of straight-through and crossover twisted pair cables.

RJ-45 Connector

The RJ-45 connector (shown in the illustration with an RJ-45 plug) is used to connect

workstations and hubs through unshielded twisted pair cable. The RJ-45 connector accepts four-

pair Category 3 or Category 5 UTP cable. Only two pairs are used for 10BASE-T wiring.

RJ-45
Connector
Pin Assignment Normal Assignment: Uplink Assignment: Port 9 on the
Model DS309 Hub
1 Input Receive Data + Output Transmit Data +
2 Input Receive Data - Output Transmit Data -
3 Output Transmit Data + Input Receive Data +
6 Output Transmit Data - Input Receive Data -
4,5,7,8 Not used Not used
Straight-through
twisted pair cable
Crossover
twisted pair cable
8146EC
Tx
Uplink or
MDI port Normal or
MDI-X port
Normal or
MDI-X port Normal or
MDI-X port
Rx
1
2
3
6Tx
Rx
1
2
3
6
1
2
3
6
1
2
3
6
Tx
Rx
Tx
Rx
711EA
18
12345678