Technical information

LS PRO OWNER'S HANDBOOK 4/11
Networking
Chapter 4
Item Description
TPE port (RJ-45 socket) The TPE port on the back of the computer
connects it to the twisted-pair Ethernet cable.
Twisted-pair Ethernet cable Cable for a twisted-pair Ethernet system can be
either unshielded twisted-pair (UTP) or shielded
twisted-pair (STP). Both types of cable consist of
two or more pairs of twisted copper wires;
however, STP has a shielding layer of foil and
copper braid around the inner cable that protects
the wiring from electromagnetic interference or
“noise”. Shielded cable is more expensive, but
recommended (e.g. Belden 9855).
The cable should meet at least the minimum
requirements of the IEEE 802.3i 10Base-T
standard: it should be of 100 ohm impedance
for a 5-10 MHz signal, and 0.5 mm or 24 AWG
in diameter. 8-core untwisted and unshielded
cable (e.g. FCC-68) is generally unsuitable and
should only be used to connect the computer
to an RJ-45 wall socket less than 2 metres away.
Maximum cable length is 100 metres. If the path
includes more than four RJ-45 plug/socket
connections, reduce the maximum length by 15
metres for each additional connection. Do not
add connections by splicing the cable.
RJ-45 connector An RJ-45 connector is located at each end of
the twisted-pair cable. To connect the cable to
the system unit, align the connector so the small
plastic tab is in line with the slot in the TPE port
(RJ-45 socket), and push in the connector until
you hear a click. (The connector is similar to
the plastic plug used to connect a telephone
cord to a wall outlet.)
Concentrator or hub The computers in a TPE system are connected
to each other by using a concentrator or hub.
Cable from each computer is plugged into a
socket at the hub.
Hubs of various capacities are readily available,
from desktop models with connectors for only
a dozen computers to rack-mounted models
which can interface over a hundred nodes.
A small network can be built by connecting a
group of computers using a single hub. For a
larger network, twisted-pair cabling can be used
to connect hubs. For greater distances still, hubs
can be connected to an Ethernet segment.