55
10BASE-T/100BASE-TX 1000BASE-T
Signal Function Signal Function
2
Tx-
Sends data
BIDA-
Bi-directional data cable A-
3
Rx+
Receives data
BIDB+
Bi-directional data cable B+
4
Reserved
N/A
BIDC+
Bi-directional data cable C+
5
Reserved
N/A
BIDC-
Bi-directional data cable C-
6
Rx-
Receives data
BIDB-
Bi-directional data cable B-
7
Reserved
N/A
BIDD+
Bi-directional data cable D+
8
Reserved
N/A
BIDD-
Bi-directional data cable D-
Table 31 RJ-45 MDIX port pinouts
Pin
10BASE-T/100BASE-TX 1000BASE-T
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-
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, router to PC and
router to switch.
•
Crossover cables connect devices of the same type—for example, switch to switch, router to
router, and PC to PC.
If an RJ-45 Ethernet port is enabled with MDI/MDIX autosensing, it can automatically negotiate pin
roles.
NOTE:
The RJ-45 Ethernet ports on the firewall support MDI/MDIX autosensing.
Making an Ethernet twisted pair cable
1.
Cut the cable to a required 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.
