   10 Mbps cabling specifications



10 Mbps Cabling Specifications
==============================

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


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

The adapter has a snap-in RJ45 connector for use with TPE 
cabling. TPE cabling is also known as RJ45 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. Contact your cable vendor for a high-
quality cable.

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

82557/8-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 an RJ45 connector on a cable
---------------------------------------
      ----------              -------------------------
     |        --|8          8 |------------             |
     |        --|7          7 |------------             |
  ---         --|6          6 |------------             |
 |            --|5          5 |------------             |
 |            --|4          4 |------------             |
  ---         --|3          3 |------------             |
     |        --|2          2 |------------             |
     |        --|1          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.


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 the adapter:

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 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-)).

The 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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