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Twisted Pair Ethernet (10baseT/UTP)

Note: most of the rules for 10BaseT are also
valid for Twisted
Pair Ethernet (100baseTX/100BaseT4)
Twisted Pair Ethernet (10baseT), sometime also called
"UTP" from "Unshielded Twisted
Pair", is based on using a cable
similar to phone-wiring. The cable is connected via an RJ-45
connectors to the network card installed in the PC.

If you have a Combo / Multi-Connector network Board, check whether you need to configure the RJ45 plug (it
is not always done automatically ! ).
These Twisted Pair cables connect now each PC to the "hub":

which is amplifying and distributing the signal to other
connected systems.

Hubs are available in different configuration,
with 4, 8, 12, 15 or 24 RJ-45 connections (and most models offer
also a BNC-connector for connection of a 10base2 Thin Ethernet
cable).
You can plug in the RJ45-connector into a hub while the network
is running on the other connected systems, allowing to move / add
systems withhaving to shutdown the network (see : Twisted Pair versus Coax:
Reliability / Advantages )
When the network grows,
you may need a second hub:

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Warning: there are different cable to
connect the hubs !
If the hub has only regular connectors, the cable MUST be
a cross-cable !
However, some hubs offer special connectors for use of
'Standard' cables
to connect between hubs (that depends on the hub, check
the hub's manual)
or a switch, able to select : 'workstation' or ' hub'
connection.
Have a look at the back of your hub:

Usually the ports are numbered, and the highest port has
a switch labeled"
"Uplink" or something like "MDI/X" in
the picture above, allowing you
to configure the port for connection to another hub using
a regular cable.
Note: if you use a regular cable to connect 2 hubs, ONLY
one hub must
configure the port for this purpose, on the other hub you
MUST connect
the cable to a regular port :
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For even larger networks, more hubs are required:

Again, watch out for the type of cable required
to connect the hubs.
Often , you find a combination of Twisted-Pair and Thin Ethernet (10base2) cabling:

A Thin-Ethernet cable is used to connect the hubs, such a cable
is then often called "the backbone", because it
carries all the traffic to/from the server.
Warning: the Thin
Ethernet (10base2) backbone MUST follow
the 10base2 specifications (length, terminators,...).
Warning: a network cannot grow unlimited in the number of hubs
and repeaters
(see: Large Networks: 5-4-3 Rule) and on very large network configurations, it may be
required to install Switches to optimize the network utilisation.
When connecting just 2 PC's together, there is a possibility to
do it without a hub:

BUT: it is now a different type of cable: a
crossed 10baseT cable.
Using a 'regular' cable (which is supposed to be used for
connection to a hub) is a common cause of error, such a 'regular'
or 'straight' 10baseT cable does NOT work in such a configuration
without a hub.
I strongly suggest to purchase a cable, but if you think you can
make it properly, here is the layout of such a crossed
10baseT-cable (i.e 10 MHz, this cable is NOT for
100baseT/100Mhz, for that look at Twisted Pair
Ethernet (100baseTX/100BaseT4) )
(please see also : www.johnscloset.net/wiring/index.html
)

pin |
|
pin |
|
1 |
<--------------------------------> |
3 |
|
2 |
<--------------------------------> |
6 |
|
3 |
<--------------------------------> |
1 |
|
4 |
< not used > |
|
|
5 |
< not used > |
|
|
6 |
<-------------------------------------> |
2 |
|
7 |
< not used > |
|
|
8 |
< not used > |
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On Category 3 or 5 grade Twisted pair cable, it should be wired
as:
Pin |
wire |
signal |
1 |
White/Orange |
Transmit - |
2 |
Orange/White |
Transmit + |
3 |
White/Green |
Receive - |
4 |
Blue/White |
|
5 |
White/Blue |
|
6 |
Green/White |
Receive + |
7 |
White/Brown |
|
8 |
Brown/White |
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where pin1 is the one on the left if you hold the RJ45 connector
with
the pins facing up. 4,5,7,8 not used in 10mb network.
To make a Cross Over patch cable for hub to hub or computer to
computer connections:
Pin |
Connector#1 |
<---cable---> |
Pin |
Connector#2 |
1 |
White/Orange |
|
1 |
White/Green |
2 |
Orange/White |
|
2 |
Green/White |
3 |
White/Green |
|
3 |
White/Orange |
6 |
Green/White |
|
6 |
Orange/White |


for distances over 10ft, the "pairs" are important for
data loss prevention.
[less errors due to electromagnetic fields].
Where is Pin#1:
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Making a
cross-cable yourself ?
You will need to invest in proper tools
(which may be more expensive
than
buying a small hub and regular cables)
More information on Self-Made Twisted Pair cables
:
www.duxcw.com
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