3Com OfficeConnect 3C16790C User manual

3Com Corporation, Corporate Headquarters, 350 Campus Drive,
Marlborough, MA 01752-3064
www.3Com.com
10016680 Rev CA June 2008
OfficeConnect®
Fast Ethernet Switch 5
(3C16790C)
Fast Ethernet Switch 8
(3C16791C)
User Guide
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About This Guide
This guide will use the term Switch when referring to the
OfficeConnect Fast Ethernet Switch.
DIMENSIONS AND STANDARDS
Dimensions and Operating Conditions
Standards
Functional: ISO 8802/3, IEEE 802.3, IEEE 802.3u
Safety: UL 60950-1, EN 60950-1, CSA 22.2
#60950-1, IEC60950-1
EMC: EN 55022 Class B, EN 55024, FCC Part 15
Class B*, ICES-003 Class B
Environmental: EN 60068 (IEC 68)
Category 5 screened cables must be used to ensure compliance with the Class
B requirements of the above standards. The use of unscreened cables complies
with the Class A requirements.
* Refer to Regulatory notices in this user guide.
3
INTRODUCTION
About This Guide:
Welcome to the world of networking with 3Com. In the
modern business environment, communication and sharing
information is crucial. Computer networks have proved to be
one of the fastest modes of communication but until recently,
only large businesses could afford the networking advantage.
The OfficeConnect®product range from 3Com has changed
this, bringing networks to the small office.
As the power of workstations and business applications increas-
es, heavier demands are made on the available network band-
width that if unchecked, can lead to performance problems in
a hub-based setup. Installing the 3Com®OfficeConnect Fast
Ethernet Switch 5 (3C16790C) or Switch 8 (3C16791C) allows
your network to be segmented so that traffic can be contained
effectively, reducing the overall load without affecting access to
critical resources. This switch has one of the most compact
designs in the industry making it ideal for desktop use. It can
be used with other units in the OfficeConnect family, which
include Cable/DSL gateways, wireless devices, Fast Ethernet and
Gigabit Ethernet switches. The OfficeConnect family is a fully
integrated system, enabling you to share computer resources,
and take advantage of new technologies as your network grows.
Your Package Contains:
• OfficeConnect Switch
• Power adapter for use with the Switch
• Four rubber feet
• This User Guide
• Warranty flyer
2
Fast Ethernet
Switch 5
2.8W, 9.56BTU/hr
Fast Ethernet
Switch 8
3.2W, 10.92BTU/hr
Depth:
Switch 5:
85 mm (3.35 in)
Switch 8:
85 mm (3.35 in)
0 to 40ºC
(32 to 104ºF)
operating
temperature
0 to 95%
(non-condensing)
humidity
Width:
Switch 5:
112 mm (4.4 in)
Switch 8:
146 mm (5.75 in)
On = 10/100M, Flash = Activity
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ABOUT YOUR SWITCH
OfficeConnect Fast Ethernet Switch - Front
1 Power LED (Illuminated Logo)
Green
Indicates that the Switch is receiving power. If the LED is
off there may be a problem with the power adapter, power
adapter cable or the Switch's internal power supply. Refer
to Problem Solving.
2 Five/Eight Port Status LEDs
Green (100 Mbps link) (10 Mbps link)
If the LED is on, the link between the port and the next
piece of equipment is OK. If the LED is flashing, the link
is OK and data is being transmitted or received. If the
LED is off, nothing is connected or the connected device
is turned off, or there is a problem with the connection
(refer to the Problem Solving section).
5
GREENCONNECT CONFIGURATION
CONFIGURATION
4
OfficeConnect
Fast Ethernet Switch 8
OfficeConnect
Gigabit Switch
On = 10/100M, Flash = Activity
Green= 1000M, Yellow= 10/100M, Flash =Activity
Figure 1
Network showing sample configuration with Fast Ethernet
Switch.
21
On = 10/100M, Flash = Activity
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WARNING: RJ-45 ports.
These are shielded RJ-45 data sockets. They cannot be used
as standard traditional telephone sockets, or to connect the
unit to a traditional PBX or public telephone network. Only
connect RJ-45 data connectors, network telephony systems,
or network telephones to these sockets.
Either shielded or unshielded data cables with shielded or
unshielded jacks can be connected to these data sockets.
VORSICHT: RJ-45-Portes.
Diese Portes sind geschützte Datensteckdosen. Sie dürfen
weder wie normale traditionelle Telefonsteckdosen noch für
die Verbindung der Einheit mit einem traditionellenm
privatenm oder öffentlichenm Telefonnetzwerk gebraucht
werden. Nur RJ-45- Datenansclußhlüsse,
Telefonnetzsysteme oder Netztelefone an diese Steckdosen
anschließen.
Entweder geschützte oder ungeschützte Buchsen dürfen an
diese Datensteckdosen angeschlossen werden.
AVERTISSEMENT : Prises RJ-45 blindées.
Ces prises ne peuvent servir comme prises téléphone
standard et ne permettent pas la connexion de l'appareil à
un système PBX ni à un réseau téléphonique public. N'y
branchez que des prises RJ-45 mâles adaptées, ou des
systèmes de réseaux téléphoniques. Il est possible d'y
brancher des câbles blindés ou non comportant des prises
de type Jack (blindées ou non).
7
OfficeConnect Fast Ethernet Switch - Rear
3 Power Adapter Socket
Only use the power adapter that is supplied with the
Switch.
4 10BASE-T/100BASE-TX Ports
Use suitable TP cable with RJ-45 connectors. You can
connect your Switch to a workstation, or any other piece
of equipment that has 10BASE-T/100BASE-TX connectivity.
Each port is capable of autosensing for 10 Mbps,
100 Mbps operation.
All ports have an automatic MDI/MDIX feature, which
means either straight-through or crossover cable can be
used to connect to any port.
6
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Wall Mounting
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.
When wall mounting the unit, ensure it is within reach
of the power outlet
When wall mounting the unit, ensure that the rubber
feet are not fixed
Mounting Instructions for Cement Walls
1Make two holes 67mm apart for 5 port, and 100mm apart
for 8 port and insert two nylon or similar screw anchors
that are suitable for the wall construction.
2Fix two suitable screws into the anchors, leaving their
heads 3 mm (0.12 in.) clear of the wall surface. The screws
should be at least 30 mm (1.2 in.) long.
3Remove 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.
Mounting Instructions for Wood Walls
1Make two holes 67mm apart for 5 port, and 100mm apart
for 8 port.
2Fix two suitable screws directly into the wall, leaving their
heads 3 mm (0.12 in.) clear of the wall surface. The screws
should be at least 20 mm (0.75 in.) long.
3Remove 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.
CAUTION: When making connections, be careful not
to push the Switch up and off the wall.
9
1 POSITIONING YOUR SWITCH
Safety Information
WARNING: Please read the ‘Important Safety
Information’ section in the Support and Safety
Information sheet before you start.
VORSICHT: Bitte lesen Sie den Abschnitt ‘Wichtige
Sicherheitsinformationen’ sorgfältig durch, bevor Sie das
Gerät einschalten.
AVERTISSEMENT: Veuillez lire attentivement la
section "Consignes importantes de sécurité" avant de
mettre en route.
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 fix-
tures, and sources of electrical noise such as radios, trans-
mitters 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 pro-
vide a minimum of 25 mm (1 in.) clearance.
Using the Rubber Feet
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.
8
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2 BEFORE YOU INSTALL YOUR SWITCH
Unit Connections
To connect other OfficeConnect units (such as gateways or
switches) to your Switch you need:
• One suitable Twisted Pair (TP) cable for each unit
3Com recommends Category 5E cable for Gigabit connections.
Workstation Connections
To connect workstations or other equipment (such as servers)
directly to your Switch, you need:
1One adapter card for each workstation to be connected to
a port on the Switch. The adapter card must be capable of
communicating at the required speed.
2 An operating system (for example Netware or Windows
95/98/Me/2000/XP) with network support configured, run-
ning on your workstations (for example Windows/Mac/
Linux).
3 One suitable Twisted Pair cable for each workstation.
1110
Wall mounting template
Fast Ethernet Switch 5 67mm apart Fast Ethernet Switch 8 100mm apart
On =10/100M, Flash= Activity
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Expanding Your Network
You can increase the number of workstations and other
devices that can connect to your network by adding
OfficeConnect gateways and switches. You can connect a
10BASE-T or 100BASE-TX OfficeConnect unit to each port of
the Switch.
The Switch has automatic MDI/MDIX functionality, and there-
fore 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.
Checking Unit Connections
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.
4 HOW YOUR SWITCH CAN BE USED
Switching
When a network of repeater hubs is in operation, any infor-
mation that is sent by the workstation is passed around the
whole network (regardless of the destination of the informa-
tion). 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".
13
3 CONNECTING WORKSTATIONS
Twisted Pair (TP) Cables
Cables can be shielded (screened) or unshielded. Cables must
be Category 5 or above. 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 out-
come will be reflected in the LEDs on the front of the Switch.
If the equipment connected to the Switch does not sup-
port autonegotiation or it has been disabled, it must be
configured to operate in half duplex mode.
12
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5 PROBLEM SOLVING
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 dam-
aged cable, or incorrect configuration. 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.
CAUTION: Do not power the Switch off and then
immediately on. Wait about five seconds between
power cycles.
Check the following symptoms and solutions:
Power Status LED (Illuminated 3Com Logo) not lit.
The power adapter or power adapter connection is likely to
be faulty. 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 or refer to the table opposite.
15
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 band-
width, connect them directly to the Switch.
Traffic Prioritization (8 port Switch only)
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 8 port 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 fea-
ture can be useful during excessive loads, for example, when
one type of traffic may require priority over another.
Connecting 10BASE-T/100BASE-TX Networks
The ports can each be connected to a 10BASE-T/100BASE-TX
network. If you have various connection speeds in your net-
work, you can join them together using the Switch allowing
all your workstations to communicate. For example, by con-
necting one of the ports to a server, all the workstations con-
nected to the server can communicate with devices connected
to the Switch, significantly increasing the size of your network.
14
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17
3C number Region
3C12VUS or 3C5VHEUS US United States
3C12VUK or 3C5VHEUK UK United Kingdom
3C12VME or 3C5VHEME ME Mainland Europe
3C12VAA or 3C5VHEAA AA Australasia
3C12VSA SA South Africa
3C12VKR KR South Korea
3C12VRA RA Argentina
Only use the power adapter supplied with the Switch
or a replacement OfficeConnect power adapter. Do
not use any other power adapter.
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 for each port that is connected. 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.
The Port Status LED is lit but the network performance of
the switch is poor. The switch supports full-duplex autonego-
tiation. If the connected device does not support autonegotia-
tion, ensure it is configured for half duplex operation only.
16
Support
and Safety
Information
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Consignes de sécurité importantes 
Avertissement: Ces avertissements sont à respecter pour votre sécurité.
Lisez-les attentivement.
Vous devez impérativement lire les consignes de sécurité suivantes avant
de procéder à l’installation ou à la désinstallation du matériel, ou à toute
activité d’entretien.
Avertissement: L’installation et la désinstallation du matériel nécessite
une vigilance exceptionnelle.
Avertissement: Pour être conforme aux normes de sécurité
internationales, ce produit doit être utilisé exclusivement avec une
alimentation aux normes du pays d’utilisation.
La sortie de l’alimentation doit être de +5/12V continus, 1A minimum, et
les polarités du connecteur de sortie doivent coïncider avec les indications
figurant sur l’appareil.
Avertissement: Coupez systématiquement l’adaptateur secteur
avant de déplacer l’appareil.
Avertissement: Cet appareil fonctionne à très basse tension de
sécurité (SELV, Safety Extra Low Voltage) conformément à la norme IEC
60950-1. Pour ce faire, le matériel auquel il est connecté doit également
fonctionner sous SELV.
Avertissement: Ports RJ 45. Il s’agit de connecteurs de
communication de données blindés RJ 45. Il n’est pas possible de les
utiliser comme prises téléphoniques classiques ni de connecter l’appareil à
un standard téléphonique classique ou à un réseau téléphonique public.
Seuls des connecteurs de réseau de données RJ 45, des systèmes de
téléphonie en réseau ou des téléphones réseau peuvent y être branchés.
Vous pouvez y brancher des câbles pour réseau de données blindés ou
non pourvus de prises jack blindées ou non aux extrémités.
19
Important Safety Information 
WARNING: Warnings contain directions you must follow for your
personal safety. Follow all directions carefully.
You must read the following safety information before carrying out any
installation or removal of the unit, or any maintenance procedures.
WARNING: Exceptional care must be taken during installation and
removal of the unit.
WARNING: To ensure compliance with international safety standards
this product must only be used with a power supply that is approved in
the country of use.
The power supply output must be +5/12V DC, 1A minimum and the
polarity of the power supply output connector must comply with the
marking on the unit.
WARNING: Disconnect the power adapter before moving the unit.
WARNING: This unit operates under SELV (Safety Extra Low Voltage)
conditions according to IEC 60950-1. The conditions are only maintained
if the equipment to which it is connected also operates under SELV
conditions.
WARNING: RJ-45 Ports. These are shielded RJ-45 data sockets. They
cannot be used as standard traditional telephone sockets, or to connect
the unit to a traditional PBX or public telephone network. Only connect
RJ-45 data connectors, network telephony systems, or network telephones
to these sockets.
Either shielded or unshielded data cables with shielded or unshielded
jacks can be connected to these data sockets.
18
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