40
Chapter 1
Internetworking
The same four wires are used in this cable as in the straight-through cable,
but we just connect different pins together. Figure 1.16 shows how the four
wires are used in a crossover Ethernet cable.
F I G U R E 1 . 1 6
Crossover Ethernet cable
Notice that instead of connecting 1 to 1, etc., here we connect pins 1 to 3
and 2 to 6 on each side of the cable.
Rolled Cable
Although this type isn't used to connect any Ethernet connections together,
you can use a rolled Ethernet cable to connect a host to a router console
serial communication (com) port.
If you have a Cisco router or switch, you would use this cable to connect
your PC running HyperTerminal to the Cisco hardware. Eight wires are used
in this cable to connect serial devices. Figure 1.17 shows the eight wires
used in a rolled cable.
F I G U R E 1 . 1 7
Rolled Ethernet cable
These are probably the easiest cables to make, because you just cut the end
off on one side of a straight-through cable and reverse the end.
Hub/Switch
Hub/Switch
1
1
2
2
3
3
6
6
Host
1
2
3
4
7
5
6
8
Router/Switch
1
2
3
4
7
5
6
8
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