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CABLE100.TXT
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1997-06-11
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100 Mbps cabling specifications
v1.07
100 Mbps cabling specifications for Intel 82557-based PCI
adapters:
EtherExpress(TM) PRO/100+ - TX
The EtherExpress PRO 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
cabling.
The type of cabling you must use depends on the adapter
you're using.
This document covers the following topics:
- EtherExpress PRO/100+ - TX adapters
- Link integrity
- Common problems
NOTE: For 10 Mbps operation, refer to the 10 Mbps cabling
specifications help file.
EtherExpress PRO/100+ TX adapters
=================================
Recommended cables
------------------
The cable must comply with the IEEE 802.3 10BASE-T standard
for 2-pair, Category 5, UTP cable. Select a high-quality
brand of Category 5 cable from your local supplier.
The cable between the computer and the hub must be less than
100 meters long.
EtherExpress PRO/100+ TX adapters do not 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, the hub provides 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 (TD+). The positive signal for the TD
differential pair. This signal contains the serial output
data stream transmitted onto the network.
2 Transmit Data Minus (TD-). The negative signal for the TD
differential pair. This contains the same output as pin 1.
3 Receive Data Plus (RD+). 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 (RD-). 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
-----------------------------------------
100BASE-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. The table below
shows which wires need to be crossed over.
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 three LEDs on the EtherExpress PRO/100+ TX
adapters:
1. A LNK light for link
2. An ACT light for activity
3. A 100 light which indicates a 100 Mbps connection
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
-----------------------------------------
Make sure hub port is configured to the correct speed. Also,
make sure last line in the NET.CFG file reads:
lastdrive=F (for NETX systems)
or
lastdrive=Z (for VLM systems)
Also try resetting the concentrator or hub or turn the power
off and on.
Polarity problems
-----------------
A common problem in 10BASE-T wiring is crossing the positive
and negative phases of the transmit or receive signals (for
example, crossing pins 1 (TX+) and 2 (TX-)).
EtherExpress PRO/100+ 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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