10 Mbps cabling specifications
                                                                    v1.05
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10 Mbps cabling specifications for Intel 82557-based PCI adapters:
     EtherExpress(TM) PRO/100B - TX
     EtherExpress(TM) PRO/100B - T4
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Specifications and recommendations for 10 Mbps cabling
======================================================

NOTE: For 100 Mbps operation, refer to the 100 Mbps cabling
      specifications help file.

This document covers the following topics:

Twisted-Pair Ethernet (TPE) cabling
===================================

The EtherExpress PRO adapters have a snap-in RJ-45 connector for use with
TPE cabling. TPE cabling is also known as RJ-45 cabling, Unshielded
Twisted Pair (UTP), and 10BASE-T cabling.

For more information on the 10BASE-T specification, contact your local
network supplier or call the IEEE at 800-678-IEEE.

Recommended cables
------------------

The RJ45 connector can use 22, 24, or 26-gauge UTP cabling. The cable
must comply with the IEEE 802.3 10BASE-T standard for Category 3, 4,
or 5.

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
Data Set           2402                 4
Belden             9566                 6

Silver Satin is not within the 10BASE-T specification and may not work or
may work intermittently.

82557-based PCI adapters don't support pre-10BASE-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.

Function     Pin#               Pin#
------------------------------------
    TX+       1    <-------->    1
    TX-       2    <-------->    2
    RX+       3    <-------->    3
    RX-       6    <-------->    6

Use only four of the eight pins. Pins 1 and 2 must be a pair, and pins 3
and 6 must be a pair.

To allow for a straight-through cable, hubs provide an internal
transmit/receive crossover function. This means the transmit circuit of
the network card is connected to the receive circuit of the hub and vice
versa.

Pinout for the RJ45 connector
-----------------------------
   ----------              -------------------------
1 |--        |          8 |------------             |
2 |--        |          7 |------------             |
3 |--         ---       6 |------------             |
4 |--            |      5 |------------             |
5 |--            |      4 |------------             |
6 |--         ---       3 |------------             |
7 |--        |          2 |------------             |
8 |--        |          1 |------------             |
   ----------              -------------------------
END                           TOP

Pin name and function:

1  Transmit Data Plus. The positive signal for the TD differential pair.
   This signal contains the serial output data stream transmitted onto
   the network.

2  Transmit Data Minus. The negative signal for the TD differential pair.
   This contains the same output as pin 1.

3  Receive Data Plus. The positive signal for the RD differential pair.
   This signal contains the serial input data stream received from the
   network.

4  Not used.

5  Not used.

6  Receive data minus. The negative signal for the RD differential pair.
   This signal contains the same input as pin 3.

7  Not used.

8  Not used.

Connecting two workstations without a hub
-----------------------------------------

10BASE-T uses a star topology. This means a hub or concentrator is 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 setup requires a
special cable incorporating the crossover function described earlier in
this document.

Function  Pin#              Pin#      Function
----------------------------------------------
TX+        1    <-------->   3        RX+
TX-        2    <-------->   6        RX-
RX+        3    <-------->   1        TX+
RX-        6    <-------->   2        TX-

NOTE: This is not an IEEE-supported configuration and should be used for
      test purposes only.
   


Link integrity
==============

There are two or three LEDs on Intel PRO adapters:

1. A LNK light for link

2. An ACT light for activity

3. 100 Mbps models also have a 100 light

Refer to your adapter Installation Guide or the "Diagnostic LEDs" Readme
file for complete information.

Note: The ACT LED indicates read/write activity on the network, not
      necessarily activity on the adapter.


Common problems
===============


A hub can't detect a workstation
--------------------------------

This is often the result of a crossed wire in the cable or wiring closet.
Make sure the wiring is correct.


Workstations can't connect to the network
-----------------------------------------

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 and receive signals (for example, crossing pins 1
(TX+) and 2 (TX-)).

EtherExpress PRO adapters automatically detect this problem and adjust
for it internally. However, it's best to check your wiring and correct
this problem if you find it.



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