3com 3c1670108 Installation Guide

Cables can be shielded (screened) or unshielded. Cables must be Category
5 or above. 3Com recommends Category 5E cable for Gigabit connections.
The maximum length you can use is 100 m (328 ft).

Twisted Pair (TP) cable is very easy to use. To connect a TP cable, simply
slot the connector into the relevant RJ-45 Port. When a connector is fully
in, its latch locks into place. To disconnect the cable, push the connector’s
latch in and remove it.

When one end of a TP cable is connected to the Switch and the other end
is connected to the network interface card of a workstation or other
device, the Switch will automatically detect whether a straight-through or
crossover cable is being used and will compensate if required. The units
will then autonegotiate to determine the fastest possible link speed
between them. This may take a few seconds and the outcome will be
reflected in the LEDs on the front of the Switch.

You can increase the number of workstations and other devices that can
connect to your network by adding OfficeConnect products. You can
connect a 10BASE-T or 100BASE-TX OfficeConnect unit to each port of the
Switch, or a 10BASE-T/100BASE-TX/1000BASE-T OfficeConnect unit to the
Gigabit Port of the Switch.

The Switch has automatic MDI/MDIX functionality, and therefore does not
require the Uplink/Normal switch associated with some OfficeConnect
products. Simply plug in the cable, and the Switch will automatically detect
which wiring practice has been followed, and will compensate accordingly.

When you have connected all your units, power on the units and the
Switch. The Port Status LEDs for the ports you have used should be lit. If

they are not, check your connections.

3 CONNECTING WORKSTATIONS

When a network of repeater hubs is in operation, any information that is sent
by the workstation is passed around the whole network (regardless of the
destination of the information). This can result in a lot of unnecessary traffic that
can slow the network down. The Switch solves this problem because it "listens"
to the network and automatically learns what workstations can be reached
through its ports. It can then selectively pass on any information by transmitting
the traffic from the relevant port only. This operation is called "switching".

The Switch effectively divides up your network, localizing the network traffic and
passing on traffic as necessary. If you have any high performance workstations
that require a lot of bandwidth, connect them directly to the Switch.

The Switch has a built in feature to aid network performance at times of
excessive load. It is called Priority Queuing. When a packet is received, the Switch
will examine it to see if it has been priority encoded. If it has, the Switch will then
read the priority level and determine whether it should be directed through the
normal or high priority channel. This feature can be useful during excessive
loads, for example, when one type of traffic may require priority over another.

The 10/100 ports can each be connected to either a 10BASE-T or 100BASE-TX
network. If you have both types of network, you can join them together using
the Switch allowing all your workstations to communicate. Alternatively, if you
use 10BASE-T and want to improve network performance by introducing
100BASE-TX technology, the Switch protects the investment in your existing
workstations because it maintains 10BASE-T connections to them.

The Gigabit port can be connected to a 10BASE-T/100BASE-TX/1000BASE-T
device, such as a workstation or a server. By connecting the Gigabit port to a
server, all the workstations connected to the server can communicate with devices
connected to the Switch, significantly increasing the size of your network.

The Switch has been designed to aid you when detecting and solving
possible problems with your network. These problems are rarely serious; the
cause is usually a disconnected or damaged cable, or incorrect configu-
ration. If this section does not solve your problem, contact your supplier for
information on what to do next.

Perform these actions first:

• Ensure all network equipment is powered on.
• Power each piece of network equipment off, wait about five seconds and

then power each one on.

Check the following symptoms and solutions:

Power Status LED or Power Adapter OK LED not lit. Refer to the
following table.

On

On

All functioning correctly

On

Off

The internal power supply has 
failed.
Contact 3Com Technical Support 
for a replacement Switch.

Off

Off

The power adapter or power 
adapter connection is faulty.
Refer to "Replacement Power 
Adapters" below.

If both the Power Adapter OK LED and Power Status LED are off, check your
power adapter connection. If there is still no power, contact 3Com Technical 

Support and ask for a replacement power adapter. Please quote the power
adapter part number, shown on the OfficeConnect power adapter you are
currently using. 

Alternatively, quote the part number for your region:

3C16740A

US and Canada

3C16741A

UK

3C16742A

Europe and Middle East

3C16743A

Japan

3C16744A

Australasia (except Japan and Korea)

3C16745A

South Africa

3C16747A

Korea

Port Status LED not lit for a port that has a TP cable connected. After
connection, it may take several seconds for the Port Status LEDs to
illuminate. The Port Status LED should turn Green, Yellow or Blue for each
port that is connected, depending on connection speed. The Duplex LED
may or may not illuminate. Please refer to ‘About Your Switch’ for a full
description of the LEDs.

If the Port Status LED is not lit after several seconds, ensure that the
connected device is powered on, that the TP cable is not damaged and that
it is correctly inserted at both ends.

You may find that a TP cable works when connected to the Switch, but that
it does not if disconnected from the Switch and connected to another
device. This may be because the other device does not have the automatic
MDI/MDIX feature.

5 PROBLEM SOLVING

To connect OfficeConnect units (such as gateways or other switches) to
your Switch you need:

• One suitable Twisted Pair (TP) cable for each unit
3Com recommends Category 5E cable for Gigabit connections.

To connect workstations or other equipment (such as servers) directly to
your Switch, you need:

1 Either:

• One 10BASE-T, 100BASE-TX or 10/100BASE-TX adapter card for each

workstation to be connected to a 10/100 Port on the Switch, or

• One 1000BASE-T adapter card for each workstation or other device

to be connected to the Gigabit port on the Switch.

3Com produce a range of easy to install network adapter cards.

2 An operating system (for example Netware or Windows 95/98/Me/2000/

XP) with network support configured, running on your workstations.

3 One suitable Twisted Pair cable for each workstation.

2 BEFORE YOU INSTALL YOUR SWITCH

4 HOW YOUR SWITCH CAN BE USED

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3C167

0108

Figure 3 Workstation connections

When positioning your Switch, ensure:

• It is out of direct sunlight and away from sources of heat.
• Cabling is away from power lines, fluorescent lighting fixtures, and

sources of electrical noise such as radios, transmitters and broadband
amplifiers.

• Water or moisture cannot enter the case of the unit.
• Air flow around the unit and through the vents in the side of the case is

not restricted. 3Com recommends you provide a minimum of 25 mm 
(1 in.) clearance.

Use the four self-adhesive rubber feet to prevent your Switch from moving
around on your desk, or when stacking with flat top OfficeConnect units.
Only stick the feet to the marked areas at each corner on the underside of
your Switch.

Use a stacking clip when stacking your Switch with other curved
OfficeConnect units. The stacking clip allows you to stack units neatly and
securely.

1 Fit the clip across the top of the unit, as shown in Figure 2 (picture 1),

ensuring that the longer sections of the fastening pieces are pointing
downwards.

2 Align the fastening pieces over the slots found on each side of the unit.
3 Push the clip down gently to secure it, ensuring that the fastening pieces

snap into the slots on the unit.

1 Rest the second unit on the top of the clip and align it with the front of

the unit below.

2 Press down gently on the unit to secure it onto the clip, ensuring the

fastening pieces fit into the slots on the unit below, as shown in Figure 2
(picture 2).

There are two slots on the underside of the Switch that can be used for wall
mounting. The Switch must be mounted with the LEDs facing upwards.

You need two suitable screws. Ensure that the wall you are going to use is
smooth, flat, dry and sturdy. Make two screw holes 150 mm (5.9 in.) apart.
Fix the screws into the wall, leaving their heads 3 mm (0.12 in.) clear of the
wall surface.

Remove any connections in the Switch and locate it over the screw heads.
When in line, gently push the Switch on to the wall and move it downwards
to secure. When making connections, be careful not to push the Switch up
and off the wall.

1 POSITIONING YOUR SWITCH

Figure 2 Stacking Your Units together

Fastening

Piece

Fastening
Piece