10BASE-T cable and pinout information
This document covers the following topics:
- Recommended cables
- Cable and connector pinouts
- Connecting two computers without a hub
- Link integrity
- Common problems
For more information on the 10BASE-T specification, contact your local
network supplier or call the IEEE (800-678-IEEE).
The EtherExpress adapters have a small, snap-in RJ45 connector.
RJ45 cabling is also known as Twisted-pair Ethernet (TPE), Unshielded
twisted pair (UTP) and 10BASE-T.
Recommended Cables
The RJ45 connector can use 22, 24, or 26-gauge UTP cabling. The cable
must comply with the IEE 802.3 10BASE-T standard.
The cable between the computer and the hub must be less than 100 meters
long.
These UTP cables work well:
Manufacturer | Model number | No. of pairs |
Belden | 9562 | 2 |
Belden | 9566 | 6 |
Data Set | 2402 | 4 |
Silver satin is not within the 10BASE-T specification and cannot be
used. If used, it may not work at all or may give intermittent results.
The EtherExpress adapters don't support pre10BASE-T concentrators.
Cable and Connector Pinouts
If you need to repair a cable or provide connectors for UTP cable, wire
straight through as shown in the following table.
Use only four of the eight pins. Pins 1 and 2 must be a pair, and pins
3 and 6 must be a pair.
Function Pin# Pin#
-------------------------------------
TX+ 1 <--------> 1
TX- 2 <--------> 2
RX+ 3 <--------> 3
RX- 6 <--------> 6
-------------------------------------
STRAIGHT THOUGH CABLE
To allow for a straight-through cable, the hub provides an internal
transmit/receive crossover function. This means the transmit circuit of
the network adapter is connected to the receive circuit of the hub and
vice versa.
Pinout for the RJ45 Connector
PINOUT FOR RJ45 CABLE CONNECTOR:
--------------------------------
---------- --------------------------
1 |-- | 8 |------------ |
2 |-- | 7 |------------ |
3 |-- --- 6 |------------ |
4 |-- | 5 |------------ |
5 |-- | 4 |------------ |
6 |-- --- 3 |------------ |
7 |-- | 2 |------------ |
8 |-- | 1 |------------ |
---------- --------------------------
END TOP
Pin Name And Function
- Transmit Data Plus. The positive signal for the TD differential
pair. This signal contains the serial output data stream
transmitted onto the network.
- Transmit Data Minus. The negative signal for the TD differential
pair. This contains the same output as pin 1.
- Receive Data Plus. The positive signal for the RD differential
pair. This signal contains the serial input data stream received
from the network.
- not connected
- not connected
- Receive data minus. The negative signal for the RD differential
pair. This signal contains the same input as pin 3.
- not connected
- not connected
Connecting Two Workstations Without a Hub
10BASE-T uses a star topology. This means there is a hub or
concentrator in the center of a star and each workstation or server is
connected to this hub.
For test purposes, you can directly connect two workstations or a
workstation and a server without using a hub. This requires a special
cable that incorporates the crossover function talked about at the
beginning of this document.
Function Pin# Pin# Function
--------------------------------------------------
TX+ 1 <--------> 3 RX+
TX- 2 <--------> 6 RX-
RX+ 3 <--------> 1 TX+
RX- 6 <--------> 2 TX-
--------------------------------------------------
CROSSOVER CABLE
Note: This is not an IEEE supported configuration and should be used for
test purposes only.
Link Integrity
For 10BASE-T networks, Link integrity (LI) needs to be on. Some
transceivers, Ethernet cards, or other network devices allow you to turn
Link Integrity off, but Link Integrity is always on with the
EtherExpress cards.
If you're using a transceiver to go to a thick/thin ethernet segment,
Link Integrity must be set to on for the transceiver.
Trouble Shooting Notes from Technical Support
A Hub Can't "See" a Workstation
A wire may be crossed in the cable or wiring closet. Check to make sure
the wiring is correct.
Workstations Can't Connect to the Network
If your workstations are having problems connecting, reset or power
off/on your concentrator or hub.
Polarity Problems
A common problem in 10BASE-T wiring is crossing the positive and
negative phases of the transmit or receive signals. For example, a
problem would occur if pins 1 and 2 were crossed. (TX+ connected to
TX-).
The current EtherExpress adapters automatically detect a polarity
problem and adjust for it internally. Early EtherExpress 16TP's didn't
have this feature.
Even though the current EtherExpress adapters can take care of the
crossover for you, it is best to check your wiring and correct polarity
problems when you find them.