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Table 35
RJ-45 MDIX port pinouts
10Base-T/100Base-TX 1000Base-T
Pin
Signal Function
Signal Function
1 Rx+
Receives
data
BIDB+
Bi-directional data
cable B+
2 Rx- Receives
data
BIDB-
Bi-directional data
cable B-
3 Tx+
Sends
data
BIDA+
Bi-directional data
cable A+
4 Reserved
N/A
BIDD+
Bi-directional data
cable D+
5 Reserved
N/A
BIDD-
Bi-directional data
cable D-
6 Tx- Sends
data
BIDA-
Bi-directional data
cable A-
7 Reserved
N/A
BIDC+
Bi-directional data
cable C+
8 Reserved
N/A
BIDC-
Bi-directional data
cable C-
The RJ-45 Ethernet ports of the firewall support MDI/MDIX autosensing. By default, MDI/MDIX
autosensing is enabled on an interface. You can use straight-through or crossover Ethernet cables.
To ensure normal communication, the pins for sending data on one port must correspond to the pins for
receiving data on the peer port. When both of the ports on the two devices are MDI or MDIX, use a
crossover Ethernet cable; when one port is MDI and the other is MDIX, use a straight-through Ethernet
cable. To summarize, straight-through and crossover cables connect the following devices:
•
Straight-through cables connect devices of different types—for example, firewall to switch and PC to
switch.
•
Crossover cables connect devices of the same type—for example firewall to firewall, and firewall to
PC.
If an RJ-45 Ethernet port is enabled with MDI/MDIX autosensing, it can automatically negotiate pin roles.
Making an Ethernet twisted pair cable
Follow these steps to make an Ethernet twisted pair cable:
1.
Cut the cable to a proper length with the crimping pliers.
2.
Strip off an appropriate length of the cable sheath. The length is typically that of the RJ-45
connector.
3.
Untwist the pairs so that they can lay flat, and arrange the colored wires based on the wiring
specifications.
4.
Cut the top of the wires even with one another. Insert the wires into the RJ-45 end and make sure
the wires extend to the front of the RJ-45 end and make good contact with the metal contacts in the
RJ-45 end and in the correct order.
5.
Crimp the RJ-45 connector with the crimping pliers until you hear a click.
