Pin assignments – H3C Technologies H3C S10500 Series Switches User Manual
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Pin assignments
Select an Ethernet twisted pair cable according to the RJ-45 Ethernet interface type on your device. An
RJ-45 Ethernet interface can be MDI (for routers and PCs) or MDIX (for switches). For the pinouts of RJ-45
and
Table 52 RJ-45 MDI interface pinouts
Pin
10Base-T/100Base-TX
1000Base-T
Signal Function
Signal
Function
1
Tx+
Send data
BIDA+
Bi-directional data cable A+
2
Tx-
Send data
BIDA-
Bi-directional data cable A-
3
Rx+
Receive 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-
Receive 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 53 RJ-45 MDI-X interface pinouts
Pin
10Base-T/100Base-TX
1000Base-T
Signal Function
Signal
Function
1
Rx+
Receive data
BIDB+
Bi-directional data cable B+
2
Rx-
Receive data
BIDB-
Bi-directional data cable B-
3
Tx+
Send 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-
Send 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 should correspond to the pins for
receiving data on the peer port. When both of the ports on the two devices are MDI or MDIX, a crossover
Ethernet cable is needed. A cross-over cable connects devices of the same type. When one port is MDI
and the other is MDIX, a straight-through Ethernet cable is needed. A straight-through cable connects
devices of different types.
If an RJ-45 Ethernet interface with MDI/MDIX autosensing enabled can automatically negotiate pin roles.
The S10500 RJ-45 Ethernet interfaces support MDI/MDIX. By default, MDI/MDIX autosensing is
enabled on a port.