9-55
Figure9-1 Console cable
Table9-1 Console cable connection
RJ-45
Signal
Direction
DB-9
1
RTS
←
7
2
DTR
←
4
3
TXD
←
3
4
CD
→
1
5
GND
-
5
6
RXD
→
2
7
DSR
→
6
8
CTS
→
8
Ethernet twisted pair cable
Introduction
An Ethernet twisted pair cable consists of four pairs of insulated copper wires twisted together. Every
wire uses a different color, and has a diameter of about 1 mm (0.04 in). A pair of twisted copper
cables can cancel the electromagnetic radiation of each other, and reduce interference of external
sources. An Ethernet twisted pair cable mainly transmits analog signals and is advantageous in
transmitting data over shorter distances. It is the commonly used transmission media of the Ethernet.
The maximum transmission distance of the Ethernet twisted pair cable is 100 m (328.08 ft). To
extend the transmission distance, you can connect two twisted pair cable segments with a repeater.
At most four repeaters can be added, which means five segments can be joined together to provide
a transmission distance of 500 m (1640.42 ft).
Ethernet twisted pair cables can be classified into category 3, category 4, category 5, category 5e,
category 6, and category 7 cables based on performance. In LANs, category 5, category 5e, and
category 6 are commonly used.
Table9-2 Description for commonly used Ethernet twisted pair cables
Type
Description
Category 5
Suitable for data transmission at a maximum speed of 100 Mbps
Category 5e
Suitable for data transmission at a maximum speed of 1000 Mbps
Category 6
Suitable for data transmission at a speed higher than 1 Gbps
Based on whether a metal shielding is used, Ethernet twisted pair cables can be classified into
shielded twisted pair (STP) and unshielded twisted pair (UTP). An STP cable provides a metallic
braid between the twisted pairs and the outer jacket. This metallic braid helps reduce radiation,
W
B
Pos.8
Pos.1
B
A
Pos.9
Pos.1
A