1-11
When working in the forced mode, Ethernet does not support MDI/MDIX autosensing.
4) Cable connecting electrical Ethernet interfaces
Ethernet electrical interfaces usually use category-5 twisted pair cables. Ethernet cables fall into two
categories:
z
Standard cables: Also known as straight-through cables. At both ends of a standard cable, wires
are crimped in the RJ-45 connectors in the same sequence. A straight-through cable is used for
connecting a terminal (for example, a PC or UTM device) to a hub or LAN switch. Straight-through
cables are shipped with the U200 series.
z
Crossover cables: At both ends of a crossover cable, wires are crimped in the RJ-45 connectors in
different sequences. A crossover cable is used for connecting two terminals (for example, two PCs
or UTM devices). You can make crossover cables yourself as needed.
Figure 1-12
Ethernet cable
Table 1-12
Straight-through cable connector pinouts
RJ-45
Signal
Category-5
twisted pair
Signal direction
RJ-45
1 TX+
White
(Orange)
Æ
1
2 TX-
Orange
Æ
2
3 RX+
White (Green)
Å
3
4 — Blue
— 4
5 — White
(Blue)
— 5
6 RX-
Green
Å
6
7 — White
(Brown)
— 7
8 — Brown
— 8
Table 1-13
Crossover cable connector pinouts
RJ-45
Signal direction
Category-5
twisted pair
Signal direction
RJ45
1 TX+
White
(Orange)
Æ
3
2 TX-
Orange
Æ
6
3 RX+
White
(Green)
Å
1