3COM 3C16700A User Manual
8.48 Mb


Ethernet Hub 4, 4C, 8, 8C

User Guide (3C16704A, 3C16703A, 3C16700A, 3C16701A)

3Com Corporation 5400 Bayfront PlazaSanta Clara, California95052-8145

Copyright © 1999, 3Com Technologies. All rights reserved.

No part of this documentation may be reproduced in any form or by any means or used to make any derivative work (such as translation, transformation, or adaptation) without written permission from 3Com Technologies.

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If there is any software on removable media described in this documentation, it is furnished under a license agreement included with the product as a separate document, in the hard copy documentation, or on the removable media in a directory file named LICENSE.TXT or !LICENSE.TXT. If you are unable to locate a copy, please contact 3Com and a copy will be provided to you.


If you are a United States government agency, then this documentation and the software described herein are provided to you subject to the following:

All technical data and computer software are commercial in nature and developed solely at private expense. Software is delivered as “Commercial Computer Software” as defined in DFARS 252.227-7014(June 1995) or as a “commercial item” as defined in FAR 2.101(a) and as such is provided with only such rights as are provided in 3Com’s standard commercial license for the Software. Technical data is provided with limited rights only as provided in DFAR252.227-7015(Nov 1995) or FAR52.227-14(June 1987), whichever is applicable. You agree not to remove or deface any portion of any legend provided on any licensed program or documentation contained in, or delivered to you in conjunction with, this User Guide.

Unless otherwise indicated, 3Com registered trademarks are registered in the United States and may or may not be registered in other countries.

3Com, the 3Com logo and OfficeConnect are registered trademarks of 3Com Corporation.

Microsoft, MS-DOS,Windows, and Windows NT are registered trademarks of Microsoft Corporation. Novell and NetWare are registered trademarks of Novell, Inc.

All other company and product names may be trademarks of the respective companies with which they are associated.

Year 2000 Compliance: For information on Year 2000 compliance and 3Com products, visit the 3Com Year 2000 Web page:http://www.3com.com/products/yr2000.html

Environmental Statement: Please recycle this user guide after use.

Please e-mailany comments about this document to 3Com at:pddtechpubs_comments@3Com.com. Please include the document title (OfficeConnect Ethernet Hub 4, Hub 4C, Hub 8, Hub 8C), part number(DUA1670-0AAA04)and, if appropriate, the page number.

Introduction 5

Creating your Network 6

What Else Do I Need? 6 Workstation Connections 6 Transceiver Connections 6 Hub Connections 7 10BASE-27


Twisted Pair (TP) Cables 7 Stacking the Units Together 8

The Rubber Feet 8

The Stacking Clip 8 Positioning Your Hub 9 Securing Your Hub 9 Using Your Hub 9

The OfficeConnect Ethernet Hub 4 and 4C 10

Ethernet Hub 4 and 4C—Front 10

Ethernet Hub 4 and 4C—Rear 11

Connecting Workstations and Other Equipment to Your Hub 12 Connecting Transceivers to the AUI Port 12

Connecting OfficeConnect Ethernet Hubs Together 12 Connecting Hubs Using 10BASE-2 13

Checking Connections 13 Connecting Hubs Using 10BASE-T 14 Checking Connections 14

Spot Checks 14

Problem Solving for the Hub 4 and 4C 15

The OfficeConnect Ethernet Hub 8 and 8C 17

Ethernet Hub 8 and 8C—Front17

Ethernet Hub 8 and 8C—Rear18

Connecting Workstations and Other Equipment to Your Hub 19 Connecting OfficeConnect Ethernet Hubs Together 19

Connecting Hubs Using 10BASE-220 Checking Connections 20 Connecting Hubs Using10BASE-T21 Checking Connections 21

Spot Checks 21

Problem Solving for the Hub 8 and 8C 22

Networking Terminology 24

Dimensions and Standards 25

Dimensions and Operating Conditions 25

Standards 25

Environmental Statements 26

End Of Life Statement 26 Regulated Materials Statement 26

Environmental Statement about the Documentation 26 Environmental Statement about the Product Packaging 26

Important Safety Information 27

Wichtige Sicherheitshinweise 28


Consignes importantes de sécurité 29

Technical Support 30

Online Technical Services 30 World Wide Web Site 30

3Com Knowledgebase Web Services 30 Support from Your Network Supplier 31 Support from 3Com 31

Returning Products for Repair 34

3Com Corporation Limited Warranty 35

Electromagnetic Compatibility 38



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 advantage of networking. The OfficeConnect® product range from 3Com has changed this, bringing networks into the small office.

The OfficeConnect Ethernet Hub 4, OfficeConnect Ethernet Hub 4C, OfficeConnect Ethernet Hub 8 and OfficeConnect Ethernet Hub 8C, are ideal for creating small networks. They are compact and attractively designed for desktop use.

These four products are part of the OfficeConnect range which stack neatly together with the OfficeConnect stacking clip.

This user guide describes how to use the OfficeConnect hubs. The hubs have similar features and so this user guide contains general and specific information. When referring to all products, this guide uses the term ‘OfficeConnect hub’.

A single OfficeConnect hub allows you to create a small network with up to four or eight workstations, as shown in Figure 1. If you need to connect more workstations, simply use the stacking clip to connect another OfficeConnect hub to form a stack (each hub is a single repeater).

Figure 1 Small Network With OfficeConnect Hub and Optional Print Server

HP JetDirect


print server

OfficeConnect hub

The OfficeConnect hubs have the following ports:

The Ethernet Hub 4 has four 10BASE-Tports.

The Ethernet Hub 4C has four 10BASE-Tports, a10BASE-2port and an AUI port.

The Ethernet Hub 8 has eight 10BASE-Tports.

The Ethernet Hub 8C has eight 10BASE-Tports and a ninth10BASE-2port.



What Else Do I Need?

Your OfficeConnect hub comes with:

One power adapter for use with the OfficeConnect hub.

A Product Registration card for you to fill out and return.

Four rubber feet.

A stacking clip.

Two unit labels and eight cable ties.

An OfficeConnect Network Assistant CD-ROM.

To connect workstations and additional OfficeConnect hubs to your hub, you need extra equipment. The extra equipment listed in the next section is not provided with the hub.

Workstation Connections

To connect workstations and other equipment to your hub, you need:

110BASE-Tconnections for all your equipment. 3Com produce a range of easy to install network adapter cards, which provide your workstations with10BASE-Tconnections.


2 1

2An operating system (for example, Netware or Windows 95/98) with network support configured, running on your workstations.

3One straight-throughTP cable for every workstation, as shown in Figure 2.

In order to comply with the 10BASE-Tstandard, ports designed for workstation connections have been marked with the graphical symbol ‘x’. This denotes a crossover in the port’s internal wiring, for example 1x, 2x, 3x...

Transceiver Connections

If you want to connect a transceiver to your hub (Hub 4C only), you need:

An AUI cable. The maximum length you can use is 50m (164ft).

A 10Mbps Ethernet transceiver for the chosen media type. 3Com produce a range of easy to use transceivers.


Hub Connections

Depending on what ports your hub has, you can use either 10BASE-Tor10BASE-2to connect your hubs together:

With 10BASE-2you can connect up to 30 hubs on a single segment, leaving all of the10BASE-Tports free.

With 10BASE-Tyou can connect up to four hubs in series.


To connect additional hubs using 10BASE-2(Hub 4C and 8C only), you need (as shown in Figure 2):

One 10BASE-250 Ohm cable for each additional hub. The minimum cable length you can use is 0.5m (1.6ft). The maximum segment length is 185m (607ft).

One 10BASE-2‘Y’ piece for each hub. You can use ‘T’ pieces but ‘Y’ pieces provide optimal clearance of the other ports.

Two 10BASE-250 Ohm terminators (end pieces).

Figure 2 Some of the10BASE-2Equipment You May Need







(end piece)

‘Y’ piece

‘T’ piece


If you have additional hubs you want to connect using 10BASE-T,you need:

Onestraight-throughTP cable for each extra hub.

Twisted Pair (TP) Cables

To connect your workstations and hubs, you must use straight-throughTP cable withRJ-45connectors. Cables can be shielded (screened) or unshielded; we recommend that you use shielded. The maximum length you can use is 100m (328ft). Astraight-throughcable is one where the pins of one connector are connected to the same pins of the other connector.


Stacking the Units Together

The Rubber Feet

The four self-adhesiverubber feet prevent your hub from moving around on your desk. Only stick the feet to the marked areas at each corner of the underside of your hub if you intend to place the unit directly on top of the desk. Do not fix the feet if you are going to use the clip.

The Stacking Clip

The blue stacking clip allows you to stack your OfficeConnect units together securely.

CAUTION: You can stack up to a maximum of four units. Smaller units must be stacked above larger units.

To fit the clip:

1Place your unit on a flat surface.

2Fit the clip across the top of the unit, as shown in Figure 3 (picture 1), ensuring that the longer sections of the fastening pieces are pointing downwards.

3Align the fastening pieces over the slots found on each side of the unit.

4Push the clip down gently to secure it, ensuring the fastening pieces snap into the slots on the unit.

To fit another unit:

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

2Press 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 3 (picture 2).

Figure 3 Stacking Your Units Together















To remove the clip:

1Remove the top unit together with the clip. If you hook a finger around one of the the fastening pieces and then pull it gently from out of the slot, the clip should come away with the upper unit attached to it.

2Push the clip in the center, so it bends towards the base of the unit, and then separate once the clip is loose.


Positioning Your Hub

When installing your OfficeConnect hub, 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. We recommend you provide a minimum of 25.4mm (1in.) clearance.

Securing Your Hub

There are two slots on the underside of the OfficeConnect hub which can be used for wall mounting. It is recommended that you mount the hubs with the LEDs facing upwards to prevent dust entering the cooling vents.

When wall mounting your hub, ensure that it is within reach of the power outlet.

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

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

CAUTION: Only wall mount single hubs, do not wall mount stacked hubs.

Also available from 3Com, is the OfficeConnect Mounting Unit (part number 3C16765). This allows you to firmly secure a stack of OfficeConnect devices to the desktop or onto a shelf in a rack.

Using Your Hub

You are now ready to create your network, using your OfficeConnect hub.

Read pages 10–16if you have an:

OfficeConnect Ethernet Hub 4 or Hub 4C

Read pages 17–23if you have an:

OfficeConnect Ethernet Hub 8 or 8C

When you have connected your equipment, you are ready to use your network. If you suspect there is a problem, refer to (depending on your hub):

“Problem Solving for the Hub 4 and 4C” on page 15

“Problem Solving for the Hub 8 and 8C” on page 22



Ethernet Hub 4 and 4C—Front

Alert LED

Activity LED

10BASE-TPort Status LEDs


(Hub 4 only)


Alerts you to excessive


Indicates the status of each 10BASE-Tport.

network use or an

Flashes each time

green — The link between the port and the next

isolated (partitioned)

a packet is

piece of network equipment is OK.


received on a

yellow — The port has partitioned due to a fault on



that segment.



off — Nothing is connected to the port or the link



has failed.

Network Utilization LEDs (Hub 4C only) green/yellow/orange

Indicates how much your network is being used.




Port Status



Network Utilization


Power ActivityCollision







1% 2% 3% 6% 12% 25% 50% 80%



Green = OK, Yellow = Partitioned






OfficeConnect Ethernet Hub 4C

Power LED

Collision LED



Indicates that the hub is

Flashes each time a collision is detected

powered on.

on the network. Collisions are part of


normal network operation.

AUI/COAX Status LEDs (Hub 4C only) green/off=media, yellow=partition

Indicates the status of the AUI or 10BASE-2port, depending on which one is in use.green/off — Theleft-handstatus LED is green if the AUI port is in use, and off if either the10BASE-2port is being used or nothing is connected to the port.

yellow — If theright-handstatus LED is yellow, the port in use has been partitioned.