3Com Switch 5108M TP User Manual

®
ONline Ethernet 10BASE-T  
Module  
Users Guide  
Document Number 17-00141-3  
Printed March 1995  
Model Number: 5108M-TP  
3Com Corporation  
118 Turnpike Road  
Southborough, MA 01772-1886  
U.S.A.  
(508) 460-8900  
FAX (508) 460-8950  
 
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Printed on recycled paper.  
ONline Ethernet 10BASE-T Module Users Guide iii  
 
iv ONline Ethernet 10BASE-T Module Users Guide  
 
Contents  
How to Use This Guide  
Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii  
Structure of This Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiv  
Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv  
Related Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvi  
3Com Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii  
Reference Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii  
Chapter 1 — Introduction  
The ONline Ethernet 10BASE-T Module . . . . . . . . . . . . . . . . . . . . . . . . . 1-1  
Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2  
Dip Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4  
Dip Switch SW1 (Port Status) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5  
Dip Switch SW3 (Crossover Mode, Channel Select, Squelch) . . . . 1-6  
Dip Switch SW6 (Link Integrity) . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9  
Related Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10  
LED and Channel Verification . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10  
The ONline Ethernet Network Management Module . . . . . . . . . 1-11  
Chapter 2 — Designing and Expanding the Netw ork  
Understanding the General Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2  
Basic Network Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2  
LAN Equivalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6  
Fiber Backbone, Twisted Pair To-The-Desk . . . . . . . . . . . . . . . . . . . . . . . 2-7  
Fiber Backbone, Twisted Pair To-The-Desk Example . . . . . . . . . . . 2-8  
Twisted Pair Backbone, Twisted Pair To-The-Desk . . . . . . . . . . . . . . . . . 2-11  
Redundant Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12  
Patch Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14  
ONline Ethernet 10BASE-T Module User’s Guide v  
 
Chapter 3 — Installing and Operating the Module  
Precautionary Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1  
Unpacking Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2  
Installation Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2  
Chapter 4 — Troubleshooting  
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1  
Troubleshooting With the Status LEDs . . . . . . . . . . . . . . . . . . . . . . . 4-1  
Troubleshooting With the Activity LEDs . . . . . . . . . . . . . . . . . . . . . . 4-5  
Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6  
Appendix A — Specifications  
ONline Ethernet 10BASE-T Module Specifications . . . . . . . . . . . . . . . . . . A-1  
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1  
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2  
Mechanical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2  
General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2  
Twisted Pair Connectors and Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3  
Twisted Pair Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3  
Twisted Pair Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4  
Connecting Twisted Pair Cables . . . . . . . . . . . . . . . . . . . . . . . . . A-5  
Appendix B — Technical Support  
On-line Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1  
Email Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2  
World Wide Web Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2  
Support from Your Network Supplier . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2  
Support from 3Com . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3  
Returning Products for Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4  
Accessing the 3Com MIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4  
3Com Technical Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5  
Index  
vi ONline Ethernet 10BASE-T Module User’s Guide  
 
Figures  
Figure 1-1.  
10BASE-T Module Faceplate and ONline  
System Concentrator . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3  
Figure 1-2.  
Figure 2-1.  
Figure 2-2.  
Figure 2-3.  
Figure 3-1.  
Figure 3-2.  
Figure A-1.  
10BASE-T Module and Dip Switch Locations . . . . . . . . . . 1-5  
Sample Configuration Distance Calculation . . . . . . . . . . . 2-9  
Unshielded Twisted Pair Network . . . . . . . . . . . . . . . . . 2-11  
Redundant Twisted Pair Configuration . . . . . . . . . . . . . 2-12  
Installing a 10BASE-T Module . . . . . . . . . . . . . . . . . . . . . 3-3  
10BASE-T Module Cable Connection . . . . . . . . . . . . . . . 3-4  
RJ45 Connector Pin-outs . . . . . . . . . . . . . . . . . . . . . . . . . A-4  
ONline Ethernet 10BASE-T Module User’s Guide vii  
 
viii ONline Ethernet 10BASE-T Module User’s Guide  
 
Tables  
Table 1-1.  
Interpretation of the 10BASE-T Module LEDs . . . . . . . . . . 1-4  
Dip Switch SW1 Settings and Interpretations . . . . . . . . . . 1-6  
Dip Switch SW3 Settings for Switches 1 and 4 . . . . . . . . . 1-7  
Table 1-2.  
Table 1-3.  
Table 1-4.  
Dip Switch SW3 Settings and Interpretations for  
Switches 2 and 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9  
Table 1-5.  
Table 1-6.  
Table 2-1.  
Table 2-2.  
Table 2-3.  
Table 4-1.  
Table 4-2.  
Dip Switch SW6 Settings and Interpretations . . . . . . . . . 1-10  
Channel Check Codes . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11  
Seven Basic Network Rules. . . . . . . . . . . . . . . . . . . . . . . . 2-3  
LAN Product Equivalent Distances . . . . . . . . . . . . . . . . . . 2-6  
Maximum Link Distance on Twisted Pair. . . . . . . . . . . . . 2-10  
Troubleshooting With the Port Status LEDs . . . . . . . . . . . 4-2  
Troubleshooting With the Port Activity LEDs. . . . . . . . . . . 4-5  
ONline Ethernet 10BASE-T Module Users Guide ix  
 
 
How to Use This Guide  
The ONlineEthernet 10BASE-T Module Users Guide describes the  
features, indicators, and installation procedures for the ONline Ethernet  
10BASE-T Module. Information on troubleshooting and diagnostics is  
included for verifying operation. This guide also contains a configuration  
section which will be helpful when you plan your network configuration.  
Audience  
This guide is intended for the following people at your site:  
Network manager or administrator  
Hardware installer  
ONline Ethernet 10BASE-T Module Users Guide xi  
 
Structure of This Guide  
This guide contains the following chapters:  
Cha pte r 1, Introductio n Introduces the principal features of the ONline  
Ethernet 10BASE-TModule and providesviews and descriptions of the front  
panel and the dip switches on the module.  
Cha pte r 2, Designing and Expa nding th e Netw ork Shows and  
explains examples of possible network configurations using the ONline  
System Concentrator and the ONline Ethernet 10BASE-T Module. These  
examples include both shielded and unshielded twisted pair configurations.  
Cha pte r 3, Installing a nd Ope ra ting the Module Providesillustrated  
procedures for installing the 10BASE-T Module into the ONline System  
Concentrator.  
Cha pte r 4, Tro ubleshootin g Provides help in isolating and correcting  
problems that mayarise during the installation process and during normal  
operation.  
Appe ndix A, Specificatio ns Provides electrical, environmental, and  
mechanical specifications, as well as other information for the module.  
Appendix B, Technical Support Lists the various methods for  
contacting the 3Com technical support organization and for accessing  
other product support services.  
Index  
xii ONline Ethernet 10BASE-T Module User’s Guide  
 
Document Conventions  
The following document conventions are used in this manual:  
Convention  
Courier text  
Indicates  
User input  
Example  
In the Agent Information Form,  
enter MISin the New Contact  
field.  
System output  
Path names  
After pressing the Apply  
button, the system displays  
the message  
Transmitting data.  
Bold command  
string  
Before you begin, read the  
readme.txt file located in  
/usr/snm/agents.  
Italic text in braces User-substituted Use the following command to  
identifiers  
show port details:  
SHOW PORT {slot.all} VERBOSE  
Capitalized text in  
plain brackets  
Keyboard entry Type your password and press  
by the user  
[ENTER].  
Italics  
Text emphasis,  
Ensure that you press the Apply  
document titles button after you add the new  
search parameters.  
ONline Ethernet 10BASE-T Module User’s Guide xiii  
 
Convention  
Note:  
Indicates  
Example  
A Note. The  
information is  
important  
Note: Use STP lobe  
cables for your system.  
Caution: A Caution. A  
condition may  
damage  
Caution: Do not put  
your installation  
diskettes on a  
software or  
hardware  
magnetic surface.  
This may damage the  
diskettes.  
Warning: A Warning. A  
condition may  
Warning: Wear eye  
protection when  
performing these  
maintenance  
threaten  
personal safety  
procedures.  
Related Documents  
This section providesinformation on suppo rting documentation, including:  
3Com Documents  
Reference Documents  
xiv ONline Ethernet 10BASE-T Module User’s Guide  
 
3Com Documents  
The following documents provide additional information on 3Com  
products:  
17-Slot ONline System Concentrator Installation and Operation  
Guide Explains how to install, operate, and manage the 3Com ONline  
17-Slot System Concentrator (Models 5017C-LS and 5017C with load  
sharing).  
6-Slot ONline System Concentrator Installation and Operation  
Guide Explains how to install, operate, and manage the 3Com ONline  
6-Slot System Concentrator.  
ONline Ethernet Management Module Installation and Operation Guide –  
Describes how to install the ONline Ethernet Network Management  
Module in the ONline System Concentrator and explains the LEDs on the  
module faceplate. This guide also provides instructions for connecting a  
terminal to the module and describes the management commands  
necessary to perform management tasks on the concentrator and on  
remote devices.  
ONline Management Commands Guide – Provides an alphabetized  
reference resource describing all ONline management commands.  
For a complete list of 3Com documents, contact your 3Com representative.  
Reference Documents  
The following documents supply related background information:  
Case, J., Fedor, M., Scoffstall, M., and J. Davin, The Simple Network  
Management Protocol, RFC 1157, University of Tennessee at Knoxville,  
Performance Systems International and the MIT Laboratory for Computer  
Science, May 1990.  
Rose, M., and K. McCloghrie, Structure and Identification of  
Management Information for TCP/IP-based Internets, RFC 1155,  
Performance Systems International and Hughes LAN Systems, May 1990.  
ONline Ethernet 10BASE-T Module User’s Guide xv  
 
 
Introduction  
1
This chapter describes the features, indicators, and dip switch settings on  
the ONline™ Ethernet 10BASE-T Module.  
The ONline Ethernet 10BASE-T Module  
The ONline™ Ethernet 10BASE-T Module is an eight-port IEEE 802.3  
repeater module that complies with the 10BASE-T standard. This module  
works with the 3Com ONline System Concentrator using both unshielded  
and shielded twisted pairwiring. The ONline 10BASE-TModule providesthe  
following features and benefits:  
supports up to 150 meter link distances on 22 gauge wire, up to 125  
meters on 24 gauge wire, and up to 100 meters on 26 gauge wire  
supports up to 200 meter link distance on IBM Type 1 cabling  
complies fully with the 10BASE-T standard  
features “hot swap” capability so that you can install or remove the  
module without having to power down the concentrator  
The 10BASE-T Module works with both unshielded and shielded twisted  
pair wire. A single module can support any mix of shielded and unshielded  
twisted pair connections. For example, ports 1, 2, and 6 can be unshielded  
Introduction 1 - 1  
 
twisted pair connections while ports 3, 4, 5, and 7 are shielded twisted pair  
connections.  
In addition to complying with the 10BASE-T standard, each port provides  
support for features that are beyond the scope of the 10BASE-T standard:  
supports shielded twisted pair cable  
allows Low Squelch level (which significantly increases achievable link  
distances)  
allows Link Integrity to be disabled (which allows connection to some  
equipment which does not conform to the 10BASE-T standard)  
Before installing the Ethernet 10BASE-T Module, read the ONline System  
Concentrator Installation and Operation Guide.  
Indicators  
The 10BASE-T Module has eight Activity and eight Status LEDs on the front  
panel that indicate the state of each port on the module. Figure 1-1 shows  
the locations of these indicators and Table 1-1 describes how to read them.  
1 - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
Figure 1-1. 10BASE-T Module Faceplate and ONline  
System Concentrator  
Introduction 1 - 3  
 
 
Table 1-1. Interpretation of the 10BASE-T Module LEDs  
LED Name  
Color  
State  
Indicates  
Activity  
(Ports 1-8)  
yellow Off  
No packetsare received on  
the segment.  
On  
Constant activity on the  
segment.  
Blinking  
Normal activity on the  
segment.  
Status  
green  
Off  
Port disabled.  
(Ports 1-8)  
On  
Port enabled and Link  
Integrity is functional.  
1 blink  
Link Integrity error.  
2 blinks  
Jabber error or port  
partitioning.  
Timed blinks (LED Link Integrity disabled for  
is on for 10  
this active port.  
seconds, blinks  
off for 400 msecs)  
Dip Sw itches  
The 10BASE-T Module has three dip switches located on the module:  
8-switch dip switch (SW1)  
4-switch dip switch (SW3)  
8-switch dip switch (SW6)  
1 - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Configure the switches to the settings you want if different than the  
default values. (Refer to Table 1-2, Table 1-3, Table 1-4, and Table 1-5 for an  
explanation of the dip switch settings.) Figure 1-2 shows the location of the  
dip switches.  
Figure 1-2. 10BASE-T Module and Dip Sw itch Locations  
Dip Sw itch SW1 (Port Status)  
The eight switches on dip switch SW1 allow you to enable or disable each  
of the eight ports. The switches are labeled 1 through 8 and correspond to  
the respective eight ports. The Off position disables the port and the On  
position enables the port. The switch settings are initially configured in the  
Introduction 1 - 5  
 
 
On position, therefore, all ports are initially enabled. Table 1-2 describes the  
settings and functions for switches 1 through 8.  
Table 1-2. Dip Sw itch SW1 Settings and Interpretations  
Factory  
Default  
Sw itch Setting  
Sw itch  
Function  
Off  
On  
1 - 8  
Enable/disable port  
enable  
disable  
enable  
If you have an ONline Ethernet Network Management Module installed in  
your concentrator, you can remotely override these switch settings. Refer to  
the ONline Ethernet Network Management Module Installation and  
Operation Guide for information on remotely managing the ports.  
Dip Sw itch SW3 (Crossover Mode, Channel Select, Squelch)  
The four switches on dip switch SW3 allow you to:  
set port 8 to uncrossed mode  
select a channel for the module  
set the Squelch level to high (normal) or low (sensitive)  
The switches are labeled 1 through 4 and the settings affect all eight ports.  
Switch 1 allows you to enable or disable crossover mode for port 8. The  
channel is initially configured for channel 1 (default) and Squelch level is  
initially configured for high (default). The following sections explain the  
crossover, channel selection, and Squelch mode.  
If you have an ONline Ethernet Network Management Module installed in  
your concentrator, you can remotely override these switch settings.  
1 - 6 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Table 1-3 explains crossover mode and squelch mode switch settings and  
the sections following the table explain these features in more detail. The  
channel selection switches are discussed in Table 1-4.  
Table 1-3. Dip Sw itch SW3 Settings for Sw itches 1 and 4  
Factory  
Default  
Sw itch Setting  
Sw itch  
Function  
Off  
On  
1
Enable/disable  
crossover mode for  
port 8 only  
enable  
disable  
(uncrossed) (crossed)  
enable  
4
Squelch mode  
high  
low  
high  
Crossover Mode Sw itch  
All eight ports on the 10BASE-T Module are internally crossed over as per  
10BASE-Tstandard. Thisenablesthe 10BASE-TModule to be connected to a  
10BASE-T Transceiver. Port 8, however, can be uncrossed using the  
crossover mode switch to connect the 10BASE-TModule directly to another  
10BASE-T Module without the need for an external crossover adapter. One  
port must be crossed over and the other port (port 8) must be uncrossed  
when connecting a 10BASE-TModule to another 10BASE-TModule. If both  
ports are crossed, you must use an external crossover adapter to provide a  
proper connection.  
The Off position disables crossover mode (uncrosses) and the On position  
enables crossover mode (default), therefore, port eight is initially crossed  
over.  
Squelch Mode Sw itch  
The Squelch mode switch allows you to set the Squelch level to high  
(normal) or low (sensitive). The On position sets the Squelch level to high  
(default). The High Squelch level conforms to the proposed 10BASE-T  
standard. In general, 3Com recommends using High Squelch.  
Introduction 1 - 7  
 
 
The Off position sets the Squelch level to low. When the Squelch level is set  
to low, the ports are able to receive weaker signals. Note that Low Squelch  
mode does not conform to the 10BASE-T standard. If you change the  
module's Squelch level to low, you must change the 10BASE-T Transceiver  
Squelch level to low also. Refer to the ONline Ethernet 10BASE-T  
Transceiver Installation Guide for information on setting the transceiver  
Squelch level.  
On unshielded twisted pair cable, setting the Squelch level to low increases  
the achievable link distance by approximately 25% to 50% , but with the  
added risk of losing packets to impulse noise. Do not use Low Squelch  
mode if your network should experience too many illegally short packets  
(runts). This problem will occur if there is significant external noise around  
the link.  
Setting the Squelch level to low in conjunction with shielded twisted pair  
wiring increases the achievable link distance without sacrificing noise  
immunity. Thus, there is no realdrawback in using Low Squelch on shielded  
twisted pair.  
To gain the extended link distance achieved by using Low Squelch mode,  
you must use qualified data grade shielded twisted pair cable or qualified  
high performance unshielded cable. IBM Type 1 shielded cable (with an  
appropriate RJ45 to Type 1 connector), among others, meets this  
requirement. If you are unsure of the grade of twisted pair cable to use, set  
the Squelch level to high, or call 3Com for a list of qualified cables to use in  
extended distance applications.  
Channel Select Sw itch Settings  
The ONline Ethernet 10BASE-T Module is equipped with the technology to  
work with the ONline System Concentrator's unique TriChannel™  
architecture. This feature allows you to assign the module to any of three  
channels (or none) on the ONline System Concentrator backplane. Refer to  
Chapter 1 in the ONline System Concentrator Installation and Operation  
Guide for a complete discussion of ONline's TriChannel architecture.  
The channel select switch settings (switches 2 and 3) on dip switch SW3 let  
you select a channel. Switches 2 and 3 are factory set to On, therefore, the  
1 - 8 ONline Ethernet 10BASE-T Module User’s Guide  
 
10BASE-T Module is initially configured to channel 1. To reconfigure the  
module to a different channel, refer to the information in Table 1-4.  
Table 1-4. Dip Sw itch SW3 Settings and Interpretations for  
Sw itches 2 and 3  
Sw itch 2  
Sw itch 3  
Channel Selection  
Switch Setting  
On  
On  
Off  
Off  
On  
Off  
On  
Off  
1 (default)  
2
3
Isolated (module  
operates independent of  
any channel)  
If you have an ONline Ethernet Network Management Module installed in  
your concentrator, you can remotely override these switch settings.  
Dip Sw itch SW6 (Link Integrity)  
The eight switches on dip switch SW6 allow you to enable or disable Link  
Integrity for each port. The switches are labeled 1 through 8 and  
correspond to the eight ports. The On position enables Link Integrity for  
each port (default) and the Off position disables Link Integrity for each  
port. The switch settings are initially configured in the On position,  
therefore, all eight ports have Link Integrity enabled, as per the 10BASE-T  
standard.  
In general, you should enable Link Integrity. To conform to the 10BASE-T  
standard, for example, a connection requires Link Integrity to be enabled.  
You must disable Link Integrity to connect to older equipment which does  
not conform to the 10BASE-T standard. Link Integrity must either be  
enabled at both ends of the link or disabled at both ends or the module will  
report a Link Integrity error.  
Introduction 1 - 9  
 
 
If you enable a port and disable Link Integrity, the Status LED is on for 10  
seconds and blinks off for 400 msecs to indicate that Link Integrity is  
disabled.  
Table 1-5 lists the settings and functions for switches 1 through 8.  
Table 1-5. Dip Sw itch SW6 Settings and Interpretations  
Factory  
Default  
Sw itch Setting  
Sw itch  
Function  
Off  
On  
1 - 8  
Enable/disable link integrity enable  
disable  
enable  
If you have an ONline Ethernet Network Management Module installed in  
your Concentrator, you can remotely override these switch settings.  
Related Features  
The following sections describe functions which allow you to:  
check the module's channel assignment and LED functionality  
remotely manage the 10BASE-T Module  
LED and Channel Verification  
The ONline Controller Module is equipped with an LED/Channel Check  
button on the front panel. The LED/Channel Check button has two  
functions: it causes all LEDs in all modules in the concentrator to light and it  
causes each module to identify the channel to which it is assigned. When  
you activate this button, it causes all module LEDs to light for  
approximately five seconds. Any LED that does not light is defective.  
After the five seconds elapse, the diagnostic continues with a channel  
check of all modules. This channel check causes each module's Status LEDs  
to blink a number of times corresponding to the channel to which it is  
1 - 10 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
assigned. The channelchecksequence repeatsfive times. Table 1-6 explains  
the channel check codes.  
Table 1-6. Channel Check Codes  
LED State  
1 Blink  
Channel Configuration  
Module is configured for channel 1  
Module is configured for channel 2  
Module is configured for channel 3  
2 Blinks  
3 Blinks  
Off  
Isolated (module operates independent of any  
channel)  
The LED/Channel Check button and the Controller Module are explained in  
more detail in the ONline Controller Module Installation Guide.  
The ONline Ethernet Netw ork Management Module  
The ONline Network Management Module provides remote network  
management capabilities for the ONline System Concentrator and its  
modules. The Management Module can also remotely override the  
following dip switch settings of the 10BASE-T Module:  
enable/disable each port  
(SET PORT 6.5 MODE ENABLE)  
enable/disable Link Integrity for each port  
(SET PORT 3.2 LINK_INTEGRITY ENABLE)  
set Squelch to high level or low level per port  
(SET PORT 5.1 SQUELCH LOW)  
enable/disable crossover mode for port 8  
(SET MODULE 5 CROSSOVER DISABLE)  
Introduction 1 - 11  
 
 
change channel selection (per module)  
(SET MODULE 4 CHANNEL 2)  
The ONline Ethernet Management Module allows you to set redundancy  
between the ports. Refer to Redundant Links in Chapter 2 for an example  
of setting redundancy between concentrators using 10BASE-T Modules.  
Refer to the ONline Ethernet Network Management Module Installation  
and Operation Guide for additional information on the Network  
Management features.  
1 - 12 ONline Ethernet 10BASE-T Module User’s Guide  
 
Designing and  
Expanding the Netw ork  
2
This appendix contains configuration information that will help you to  
design your network. Install all equipment using only approved cables for  
proper operation. Refer to Appendix A in the Twisted Pair Connectors and  
Cables section for information on twisted pair connector and cable  
requirements.  
This appendix describes how to configure your network with the ONline  
System Concentrator and the ONline Ethernet 10BASE-T Module. It also  
provides examples of alternative network cabling structures and rules for  
configuring Ethernet networks. There are five sections:  
Network Diameter Calculations: General Rules  
Fiber Backbone, Twisted Pair To-The-Desk  
Twisted Pair Backbone, Twisted Pair To-The-Desk  
Redundant Links  
Patch Panels  
Designing and Expanding the Network 2 - 1  
 
Understanding the General Rules  
As part of your network design, it is important to consider your network  
size. For instance, is the network (end-to-end) 100 meters, 1000 meters,  
4000 meters, or more? What are your plans for expansion? Your answers  
play a role in how you configure your network. For example, once the  
network expands beyond a certain size, you need to add a bridge or other  
internetworking device.  
This section describes general rules for configuring an Ethernet network  
using fiber as the backbone medium. It also provides rules to ensure that  
your network configuration conforms to distance limitations imposed by  
Ethernet and networking equipment.  
This section includes:  
Basic Network Rules  
LAN Equivalence  
Basic Netw ork Rules  
This section outlines the basic network rules and 3Com recommendations  
for these rules. For more hardware-specific information on the 10-Port  
module, refer to Appendix A.  
2 - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
Table 2-1 outlinesthe seven basic rules to keep in mind when you construct  
your network.  
Table 2-1. Seven Basic Netw ork Rules  
Rule  
Definition  
Recommendations/Notes  
1
If possible, use  
10BASE-FB as the  
backbone medium.  
Use 62.5 micron cable to conform  
with the IEEE 10BASE-F and  
upcoming ANSI FDDI standards.  
Use ST-type connectors.  
2
Wire the backbone in Make sure to lay extra fiber cables.  
a star topology to  
isolate faults.  
The extra cost is small and you will  
find you need them asyour network  
grows.  
The star topology conforms to FDDI  
wiring as well -- just make sure to  
run at least two fiber strands to  
every backbone connection.  
3
The maximum Fiber  
Ethernet network  
diameter is 4200  
The 4200 meters is the maximum  
distance between any two  
transceivers on the network.  
meters of fiber cable.  
The 4200 meters does not include  
the transceivercable (that is, drop or  
patch cable) that connects a device  
with an external transceiver.  
Transceiver cables can extend up to  
50 meters. Thus, total network  
diameter can be as much as 4300  
meters (4200 m + 2 * 50 m)  
between any two nodes.  
Designing and Expanding the Network 2 - 3  
 
 
Table 2-1. Seven Basic Netw ork Rules (Continued)  
Rule  
Definition  
Recommendations/Notes  
4
Certain LAN devices  
Many LAN products delay the signal  
on the network shrink that goes through them. This is  
the maximum Fiber  
Ethernet network  
diameter to less than  
4200 meters.  
known as equivalent distance. Every  
microsecond delay reduces the  
maximum link distance. In fact,  
every microsecond delayshrinks the  
network diameter by approximately  
200 meters of fiber cable. Table 2-2  
lists the Equivalent Distances for  
other 3Com products.  
5
Assume that one  
meter of coaxial or  
This is a conservative rule of thumb.  
For example, the actual equivalence  
twisted pair is equal to is about 1.1 meters of coaxial for  
one meter of fiber  
cable.  
every meter of fiber. For simplicity,  
assume one meter.  
2 - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
Table 2-1. Seven Basic Netw ork Rules (Continued)  
Rule  
Definition  
Recommendations/Notes  
6
The fiberlinkdistances In general, on 62.5 micron cable,  
must not exceed the  
limits imposed by the  
you can go up to 4000 meters  
point-to-point using the ONcore or  
optical power budget. ONline Fiber Modules. If you have  
poor quality cable or cross many  
patch panels, you may have to  
sacrifice some distance.  
Some older Ethernet fiber optic  
products are less powerful than  
ONcore Fiber Module optics. So  
when connecting to these products,  
remember that the least powerful  
device determines the maximum  
point-to-point distance.  
7
When in doubt, use a If you are not certain if you have  
bridge.  
exceeded allowable network  
distances, use a bridge to extend  
the network.  
Designing and Expanding the Network 2 - 5  
 
LAN Equivalence  
LAN equivalence is the sum of both the incoming and outgoing module  
port signals. Different modules, however, have different equivalent  
distances. Table 2-2 lists the LAN product equivalent distances.  
Table 2-2. LAN Product Equivalent Distances  
Equivalent  
LAN Product  
Distance (meters)  
ONcore Ethernet 10-Port 10BASE-FB Module  
Incoming signal to fiber port  
190  
140  
50  
Outgoing signal from fiber port  
ONcore Ethernet 10BASE-T Module  
Incoming signal to TP port  
585  
420  
165  
585  
420  
165  
190  
140  
50  
Outgoing signal from TP port  
ONline Ethernet 10BASE-T Modules  
Incoming signal to TP port  
Outgoing signal from TP port  
ONline Ethernet Fiber or 10BASE-FB Modules  
Incoming signal to fiber port  
Outgoing signal from fiber port  
ONline Ethernet FOIRL Module  
Incoming signal to fiber port  
560  
330  
230  
0
Outgoing signal from fiber port  
ONline Ethernet Transceiver Module  
10BASE-FB Star Coupler (8 or 14 port) 26  
180  
2 - 6 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Table 2-2. LAN Product Equivalent Distances (Continued)  
Equivalent  
Distance (meters)  
LAN Product  
ONline Ethernet BNC Module  
Incoming signal to BNC port  
Outgoing signal from BNC port  
ONline Ethernet Repeater Module  
Incoming signal to AUI port  
Outgoing signal from AUI port  
IEEE Repeater  
900  
450  
450  
800  
600  
200  
800  
Fiber Backbone, Tw isted Pair To-The-Desk  
When you configure a network with unshielded or shielded twisted pair  
cabling to-the-desk and fiber for the backbone, there are only three  
additional rules you need to be aware of:  
There can be no more than eight 10BASE-T Modules (5108M-TP) in  
the path between any two transceivers due to Ethernet's  
four-repeater rule (each 10BASE-T Module counts as a 1/2 repeater).  
You must add a bridge if you have more than eight 10BASE-T  
Modules serially connected.  
There is an equivalent fiber distance for the ONline Fiber Modules  
(see Rule 4). The equivalent is:  
140 metersforsignalsthat externallyentera FiberModule  
port  
50 meters for signals that internally enter a Fiber Module  
via the ONline Concentrator backplane  
Designing and Expanding the Network 2 - 7  
 
There is an equivalent fiber distance for the 10BASE-T Modules (see  
Rule 4). The equivalence is:  
420 meters for signals that externally enter a 10BASE-T  
Module port  
165 meters for signals that internally enter a 10BASE-T  
Module via the ONline Concentrator backplane  
Thus, for every pair of 10BASE-T Modules that a signal goes through, there  
is a fiber equivalent distance of 585 meters (420 m + 165 m = 585 m). This  
is also true if a signal makes a roundtrip through a single 10BASE-TModule,  
i.e., enters a 10BASE-T port externally and exits through another port on  
the same 10BASE-T Module. This counts as 585 meters of fiber equivalent  
distance, and as a full repeater.  
Fiber Backbone, Tw isted Pair To-The-Desk Example  
In the sample configuration shown in Figure 2-1, we determine if the  
transceivers are within legal Ethernet limits. This example is applicable to  
both unshielded and shielded twisted pair cables. Note that 22 gauge  
unshielded twisted pair cable is used to connect 10BASE-T Transceivers to  
the 10BASE-T Modules in the concentrators.  
The first step is to identify the two transceivers that are likely to be the  
greatest fiber equivalent distance apart. In this case, they are 10BASE-T  
Transceivers A and B.  
2 - 8 ONline Ethernet 10BASE-T Module User’s Guide  
 
.
Figure 2-1. Sample Configuration Distance Calculation  
Use the following steps to determine whether your network configuration  
is legal:  
1. Begin with 4.2 km (4200 m) since this is the maximum network  
diameter for a pure fiber network (Rule 3).  
2. Subtract 100 m for the signal exiting the Fiber Modules in  
concentrators A and C (2 * 50) and 280 m for the signal entering the  
Fiber Modules in concentrators C and B (2 * 140) as explained in Rule  
4 and defined in Table 2-2.  
3. Subtract 420 m of fiber equivalent distance for the signal entering the  
10BASE-T Module in concentrator A and 165 m for the signal exiting  
the 10BASE-T Module in concentrator B (Rule 4).  
4. Subtract all cable lengths between the two transceivers and if the  
result is greater than zero, the configuration is within legal Ethernet  
limits (Rule 5).  
Designing and Expanding the Network 2 - 9  
 
 
For the configuration shown in Figure 2-1 to work, the fiber equivalent  
distance between transceiver A and transceiver B must be less than 4200  
meters. As you can see in the calculation, there are still 1510 meters left for  
expansion in this configuration.  
Be aware that the link from a 10BASE-T Module to a 10BASE-T Transceiver  
should not exceed the distances as defined in Table 2-3. In this example,  
the link cannot exceed 150 meters, using the 10BASE-T standard High  
Squelch mode and 22 gauge wire.  
Table 2-3. Maximum Link Distance on Tw isted Pair  
Cable Gauge  
Supports Link Distances Up To:  
Unshielded Tw isted Pair: High Squelch  
10BASE-T  
Low Squelch  
22 (.6mm)  
24 (.5mm)  
150m  
125m  
200m  
150m  
Shielded Tw isted Pair:  
IBM Type 1  
High Squelch  
Low Squelch  
22 (.6mm)  
200m  
300m  
In areas of low noise, the Squelch level can be lowered to accept weaker  
signals. (Low Squelch does not conform to the 10BASE-T standard.) This  
allows the acceptable linkdistance to increase to 200 meters. The 10BASE-T  
standard limits link distance to approximately 200 meters (equivalent to  
1 µsec of delay) on unshielded twisted pair.  
10BASE-T signaling can also be used on shielded twisted pair even though  
the standard does not include shielded twisted pair in its specification.  
Since external noise does not affect signals on shielded twisted pair, there is  
no restriction in using the Low Squelch level. Using Low Squelch on  
shielded twisted pair allows link distances of up to 300 meters.  
Nevertheless, 3Com recommends that you always use the High Squelch  
setting except in situations where the link distance exceeds 200 meters.  
2 - 10 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Tw isted Pair Backbone, Tw isted Pair To-The-Desk  
In constructing a twisted pair backbone, one add itional configuration rule  
must be considered:  
There can be no more than eight 10BASE-T Modules in the path  
between any two transceivers due to the Ethernet four-repeater  
rule (each 10BASE-T Module counts as a 1/2 repeater). You must  
add a bridge if you have more than eight 10BASE-T Modules  
serially connected.  
The configuration in Figure 2-2 illustrates a possible unshielded twisted pair  
network using 22 gauge cable.  
Figure 2-2. Unshielded Tw isted Pair Netw ork  
Note that when connecting two concentrators with twisted pair cable, use  
port 8 on one of the 10BASE-T Modules and disable crossover mode for  
that port. This allows a direct connection to another 10BASE-T Module  
without the need for an intervening adapter. (Refer to Dip Switch SW3  
(Crossover Mode, ChannelSelect, Squelch)in Chapter 1 for information on  
crossover mode and the crossover mode switch setting.)  
Designing and Expanding the Network 2 - 11  
 
 
While there is no fiber in this configuration, the fiber equivalent distance  
can be calculated as follows:  
Total link distance: 150 m + 100 m + 100 m + 50 m + 20 m = 420 m  
Total equivalent distance of 10BASE-T Modules:  
4 * 420 m + 4 * 165 m = 2340 m  
(signal externally enters four 10BASE-T Modules: 4 * 420 m)  
(signal enters four 10BASE-T Modules from the backplane: 4 * 165 m)  
Total equivalent distance: 420 m + 2340 m = 2760 m  
Since the total equivalent distance (2760 m) is less than 4200 meters, this is  
a legitimate configuration.  
Note that if shielded twisted pair cabling is used, each link in the network  
could run up to 300 meters using Low Squelch (refer to Dip Switch SW3  
(Crossover Mode, ChannelSelect, Squelch)in Chapter 1 for information on  
Squelch levels and the Squelch dip switch setting). Low Squelch is  
acceptable for all shielded twisted pair applications since external noise is  
not a problem.  
Redundant Links  
You can implement twisted pair link redundancy between ONline System  
Concentrators using Network Management. Figure 2-3 below shows an  
example of a redundant configuration between concentrators using  
10BASE-T Modules.  
Figure 2-3. Redundant Tw isted Pair Configuration  
2 - 12 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
To set redundancy between two 10BASE-T Modules, connect two links  
between the modules. The redundant link must be connected to a port on  
the same 10BASE-T Module as the primary link. Use a crossover adapter  
between each link unless you choose to uncross port 8 on one of the  
modules to make the connection. Refer to Chapter 1 for information on  
using crossover mode. Then use the SET PORT <slot.port> MODE  
REDUNDANT <slot.port> command to specify which port is the primary link  
and which is the backup link.  
Note: If the 10BASE-T Modules are powered down, and then  
brought back up without the Ethernet Management  
Module present, a network loop could occur. To prevent a  
potential failure, 3Com advises that you disable the Port  
Enable dip switch setting for the backup port on one of the  
10BASE-T Modules.  
Once redundancy is configured, a switchover will occur under three  
conditions: a link failure; port partition; or a jabber condition. The  
switchover occurs when the primary link fails. (Note that in the unlikely  
event of a partial break in the link, a switchover may not occur. In this  
situation, use Network Management to manually switch over the ports.)  
Once the switchover occurs, and the primary link becomes operational, a  
switch-over back to the primary link happens automatically if the cause of  
the original switchover was a link failure. If a jabber condition causes the  
switchover, the link will not automatically switch back to the primary once  
the problem is resolved. In this case, use Network Management to  
manually switch back to the primary link.  
Refer to the ONline Ethernet Network Management Module Installation  
and Operation Guide for information on setting redundancy between  
10BASE-T Module ports.  
Designing and Expanding the Network 2 - 13  
 
Patch Panels  
Patch panels weaken signals, thereby reducing achievable link distances.  
3Com includes the use of one patch panel in the 150 meter link distance  
calculation. However, each additional patch panel in the link reduces the  
150 meter link distance by approximately 10 meters.  
In the example in Figure 2-2, if two patch panels were used between the  
top right PC and the top right concentrator, the link distance of 150 meters  
would have to be shortened to 140 meters. This is because the maximum  
allowable linkdistance on 22 gauge wire using 10BASE-Tsignaling with two  
intervening patch panels is 150 meters minus approximately 10 meters.  
Note that a patch panel installed between the bottom right PC and the  
bottom left concentrator would not affect the link since it is only 20 meters.  
2 - 14 ONline Ethernet 10BASE-T Module User’s Guide  
 
Installing and  
Operating the Module  
3
This chapter describes the precautionary, unpacking, and installation  
procedures for the Ethernet 10BASE-T Module.  
Precautionary Procedures  
Electrostatic discharge (ESD) can damage static-sensitive devices on circuit  
boards. Follow these precautions when you handle the 10BASE-T Module.  
Do not remove the board from its anti-static shielding bag until you  
are ready to inspect it.  
Handle the board by the faceplate.  
Use proper grounding techniques when you install the 10BASE-T Module.  
These techniques include using a foot strap and grounded mat or wearing  
a grounded static discharge wrist strap. An alternate method is to touch  
the grounded rack or other source of ground just before you handle the  
module.  
Installing and Operating the Module 3 - 1  
 
Unpacking Procedures  
Use the following procedure when unpacking your 10BASE-T Module.  
1. Verify that the 10BASE-T Module is the correct model by matching  
the model number listed on the side of the shipping carton to the  
model number you ordered (5108M-TP).  
Note that the product model number printed on the shipping box  
differs from the model number on the product. The model number  
on the shipping box contains the prefix ’3C9.  
2. Remove the 10BASE-T Module from the shipping carton.  
3. Remove the module from the anti-static shielding bag and inspect it  
for damage. Always handle the 10BASE-T Module by the faceplate  
being careful not to touch the components.  
If the module appears to be damaged, replace it in the anti-static  
shielding bag, return it to the shipping carton, and contact your local  
supplier.  
3Com suggests you keep the shipping carton and anti-static shielding bag  
in which your module was shipped in case you later want to repackage the  
module for storage or shipment.  
We also suggest that you record the serial number of your 10BASE-T  
Module. We have provided a log for this and other information specific to  
your modules under the Slot Usage Chart in Appendix B of the ONline  
System Concentrator Installation and Operation Guide.  
Installation Procedures  
You do not need to power down the ONline System Concentrator to install  
the 10BASE-T Module. You can insert the module while the concentrator is  
operating (called a hot insertion). Follow the steps below to install the  
10BASE-T Module.  
3 - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
1. Set the dip switches on the board to the settings you want, if  
different than the default values. (Refer to Table 1-2, Table 1-3,  
Table 1-4, and Table 1-5 for an explanation of the dip switch settings.)  
2. Locate a blank slot in the concentrator. If there is no blank slot, you  
must remove a blank panel on the concentrator to expose a slot for  
3. Insert the module into the board guides at the top and bottom of the  
slot and slide it into the concentrator. Makesure the connector is well  
seated into the backplane of the concentrator.  
Figure 3-1 shows the installation of the 10BASE-T Module.  
Figure 3-1. Installing a 10BASE-T Module  
Installing and Operating the Module 3 - 3  
 
 
4. Fasten the spring-loaded screws on the front of the 10BASE-TModule  
face-plate to the concentrator with your fingers (do not overtighten).  
5. Attach the twisted pair cable to the port on the front of the 10BASE-T  
Module as shown in Figure 3-2. Then attach the other end of the  
cable to another 10BASE-T Module, a 10BASE-T Transceiver, or a  
10BASE-T Adapter Card.  
Figure 3-2 shows a cable attached to the 10BASE-T Module.  
Figure 3-2. 10BASE-T Module Cable Connection  
3 - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Troubleshooting  
4
This chapter describes troubleshooting procedures for the ONline Ethernet  
10BASE-T Module. Information on troubleshooting will assist you in  
verifying operation. Typical fault conditions are addressed in this chapter.  
Troubleshooting  
Diagnostic features are covered in Table 1-1 on page 1-4. Table 4-1 and  
Table 4-2 in this chapter cover fault conditions and troubleshooting  
suggestions for the 10BASE-T Module. This chapter is divided into the  
following parts:  
Troubleshooting With the Port Status LEDs  
Troubleshooting With the Activity LEDs  
Technical Assistance  
Troubleshooting 4 - 1  
 
Troubleshooting With the Status LEDs  
A blinking Port Status indicator may be a sign that the port detects a  
potential problem. Once a port detects a problem, you can further analyze  
the problem by counting the number of blinks. Table 4-1 provides  
troubleshooting suggestions for each of the blinking sequences.  
Table 4-1. Troubleshooting With the Port Status LEDs  
Possible  
Problem  
Troubleshooting  
Suggestions  
LED State  
Indication  
Off  
Port  
Port disabled  
Enable port.  
Disabled  
10BASE-T  
Module not  
powered  
Check the Controller  
Module Power LEDs.  
Broken LED  
Press the LED/Channel  
Check button on the  
Controller Module.  
Bad 10BASE-T  
Module  
Replace module.  
4 - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Table 4-1. Troubleshooting With the Port Status LEDs (Continued)  
Possible  
Problem  
Troubleshooting  
Suggestions  
LED State  
Indication  
1 Blink  
Link  
Cable not  
Connect cable.  
Integrity  
Error  
connected  
Cable broken  
Check cable with cable  
tester. Repair or replace  
cable.  
Cable too long  
Try a shorter cable.  
Remote  
Enable Link Integrity at  
remote connection or if  
the remote linkdoesnot  
have Link Integrity,  
connection has  
Link Integrity  
disabled  
disable Link Integrity at  
local connection.  
Weak or no  
signal - link  
distance too  
long  
Change Squelch level  
from high to low (low  
setting does not  
conform to the  
10BASE-T standard).  
Bad port  
Try another port.  
Device attached This is not a problem.  
to transceiver at  
other end is not  
powered on  
Troubleshooting 4 - 3  
 
Table 4-1. Troubleshooting With the Port Status LEDs (Continued)  
Possible  
Problem  
Troubleshooting  
Suggestions  
LED State  
Indication  
2 Blinks  
Port  
Partitioning  
Faulty cable  
Check cable with cable  
tester. Repair or replace  
cable.  
Network  
overloaded  
Reassign users to  
another channel to  
balance the load.  
Jabber  
condition  
Transceiver  
attached to the  
port is jabbering  
or has DTE  
jabber  
Try another port or  
replace module.  
Timed  
Link  
None  
This is not a problem.  
You may want Link  
Integrity disabled.  
Blinks (LED Integrity  
is on for 10 Disabled  
seconds,  
blinks off  
for 400  
msecs)  
4 - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
Troubleshooting With the Activity LEDs  
There may be situations where a port's Activity LED maynot light. Use the  
troubleshooting suggestions in Table 4-2 to help isolate why this has  
occurred.  
Table 4-2. Troubleshooting With the Port Activity LEDs  
LED  
State  
Troubleshooting  
Solutions  
LED Name  
Possible Problem  
Activity  
(Ports 1 - 8)  
Off  
There is no traffic  
received from the  
segment (normal)  
None.  
The port is disabled Check the port enable dip  
switch setting.  
The power is off  
Check the Controller  
Module Power LEDs.  
The Activity LEDhas Press the LED/Channel  
burnt out  
Check button on the  
Controller Module.  
The 10BASE-T  
Module port is  
faulty  
Connect the cable to a  
different port.  
The module  
connection to the  
backplane is bad  
Reinsert the 10BASE-T  
Module. If this fails, try  
anotherconcentratorslot.  
The 10BASE-T  
Module is faulty  
Try a different 10BASE-T  
Module.  
Troubleshooting 4 - 5  
 
 
Technical Assistance  
You can receive assistance for installing and troubleshooting the 10BASE-T  
Module by calling either your 3Com reseller or 3Com Technical Support. Be  
prepared to supply a representative with the following information:  
Description of the problem  
Steps you have taken to try and correct the problem  
Type and software version of the ONline network management  
module being used  
Version of software installed on your 10BASE-T Module  
Status of the front panel LEDs  
Configuration of your concentrator  
(you may find it helpful to refer to the Slot Usage Chart in Appendix B  
of the ONline System Concentrator Installation and Operation Guide  
for a record of this information)  
Reber to Appendix B for instructions on contacting Technical Support for  
your product.  
4 - 6 ONline Ethernet 10BASE-T Module User’s Guide  
 
Specifications  
A
ONline Ethernet 10BASE-T Module Specifications  
This appendix lists specifications for the 10BASE-T Module. There are five  
subsections:  
Electrical Specifications  
Environmental Specifications  
Mechanical Specifications  
General Specifications  
Twisted Pair Connectors and Cables  
Electrical Specifications  
Backplane Interface: 96-pin edge connector, compatible with the 3Com  
ONline System Concentrators.  
Power Requirements: 1.75 A for 5V  
Fuse: 4.0 Amps Fast blow  
Watts: 8.75  
Specifications A - 1  
 
Environmental Specifications  
Operating Temperature: 0° to 50° C (32° to 122° F)  
Storage Temperature: -30° to 65° C (-22° to 149° F)  
Humidity: less than 95% , non-condensing  
BTU/hr: 30  
Mechanical Specifications  
Dimensions: 1.0" W x 10.25" L x 8.5" H  
(2.54 cm x 26.04 cm x 21.6 cm)  
Weight: 1.25 lb. (0.57 kg.)  
General Specifications  
Data Rate: 10 Mbps (million bits per second)  
Data modulation: Manchester  
Diagnostic modulation: Link Integrity pulse  
Collision detection: 100% deterministic  
Maximum number of nodes: 1024  
Configuration rules: supports IEEE 802.3 controllers and IEEE 802.3  
repeaters  
Jabber Protection: 6.5 milliseconds  
Port Connectors: Shielded 8-pin modular telephone jack, compatible with  
an unshielded connector  
Cabling: 22, 24, or 26 AWG unshielded or shielded twisted pair cable  
Cable differential impedance: 85 ohms to 150 ohms over 1 to 16 MHz band  
A - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
Cable propagation velocity: >.585c  
Host Interface: 3Com ONline System Concentrator bus interface standard  
Installation Attachment: Two thumbscrews on the mounting bracket  
Tw isted Pair Connectors and Cables  
There are many types of cables and connectors that you can use to link  
your 10BASE-T Module to your network. These cables and connectors are  
explained in the following sections. Use this information to ensure that the  
cables and connecting hardware meet requirements. For proper operation,  
use only approved cables when you install all equipment. This section is  
divided into the following parts:  
Twisted Pair Connectors  
Twisted Pair Cables  
Tw isted Pair Connectors  
The IEEE802.3 10BASE-Tstandard for pin-outs must be used. The following  
cable standard must be used. 10BASE-T uses 2 pairs of wire: pins 1 & 2 and  
pins 3 & 6. If the pairs are not configured this way, the connection will not  
work properly. Datagrade cable should have the following pin pairings:  
pins 4 and 5 are pair 1  
pins 3 and 6 are pair 2  
pins 1 and 2 are pair 3  
pins 7 and 8 are pair 4  
Specifications A - 3  
 
Refer to Figure A-1 for an example of this connector and the cable pin-outs.  
Pair 2  
Pair 3  
Pair 1  
Pair4  
1
2
3
4
5
6
7
8
W-G  
G
W-O BL W-BL O W-BR BR  
Jack Positions  
Figure A-1. RJ45 Connector Pin-outs  
Some installations may have 50-pin Telco connectors at the wiring closet.  
We recommend using a patch panel that converts from 50-pin to RJ45-type  
connectors. This allows direct connection to the ONline Ethernet 10BASE-T  
Module in your ONline System Concentrator.  
Tw isted Pair Cables  
The cables that are supported must meet the following qualifications:  
22, 24, or 26 gauge twisted pair cable  
80 to 150 ohm impedance  
minimum of 2 pairs  
Usually, a pair on a twisted pair cable is designated by a solid color wire  
twisted with a striped wire with the same color.  
A - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
 
Connecting Tw isted Pair Cables  
We recommend that you connect cables first at the active concentrator  
location, and connect transceivers second. Refer to the ONline System  
Concentrator Installation and Operation Guide for more information about  
the ONline System Concentrator connections.  
Specifications A - 5  
 
 
Technical Support  
B
3Com provides easy access to technical support information through a  
variety of services. This appendix describes the following services:  
On-line Technical Support  
Support from Your Network Supplier  
Support from 3Com  
Returning Products for Repair  
Accessing the 3Com MIB  
3Com Technical Publications  
On-line Technical Support  
3Com offers worldwide product support through the following on-line  
systems:  
Email Technical Service  
World Wide Web Site  
Technical Support B - 1  
 
Email Technical Support  
You can contact the Integrated Systems Division (formerly Chipcom) on the  
Internet for technical support using the e-mail address  
techsupp@chipcom.com.  
World Wide Web Site  
You can access the latest networking information on the 3Com World  
Wide Web site by entering our URL into your Internet browser:  
This service features news and information about 3Com products,  
customer service and support, the 3Com latest news releases, selected  
articles from 3TECH , the 3Com award-winning technical journal, and  
more.  
You can contact the Integrated Systems Division on the World Wide Web  
by entering our URL into your Internet browser:  
There are links between both WWW pages to view information from all  
3Com divisions.  
Support from Your Netw ork Supplier  
If additional assistance is required, contact your network supplier. Many  
suppliersare authorized 3Com service partnerswho are qualified to provide  
a variety of services, including network planning, installation, hardware  
maintenance, application training, and support services.  
B - 2 ONline Ethernet 10BASE-T Module User’s Guide  
 
When you contact your network supplier for assistance, have the following  
information ready:  
Diagnostic error messages  
A list of system hardware and software, including revision levels  
Details about recent configuration changes, if applicable  
If you are unable to contact your network supplier, see the following  
section on how to contact 3Com.  
Support from 3Com  
If you are unable to receive support from your network supplier, technical  
support contracts are available from 3Com.  
For direct access to customer service for Integrated Systems Division  
products in:  
U.S.A. and Canada - call (800) 724-2447  
Asia Pacific - call (508) 787-5151  
Europe - Refer to the table below. For European countries not listed,  
call 31 30 60 299 00.  
Country  
Belgium  
Denmark  
Finland  
France  
Telephone Number  
0800 71429  
800 17309  
Country  
Netherlands  
Norway  
Spain  
Telephone Number  
06 0227788  
800 11376  
0800 113153  
05 917959  
900 983125  
Sweden  
U.K.  
020 795482  
Germany  
Ireland  
0130 821502  
1 800 553117  
1678 79489  
0800 966197  
800 876-3266  
U.S.  
Italy  
Technical Support B - 3  
 
For access to customer service for all 3Com products, call (800) 876-3266.  
You can also contact the Integrated Systems Division (ISD) on the Internet  
by using the e-mail address techsupp@chipcom.com.  
Returning Products for Repair  
A product sent directly to 3Com for repair must first be assigned a Return  
Materials Authorization (RMA) number. A product sent to 3Com without  
an RMA number will be returned to the sender unopened, at the senders  
expense.  
To obtain an RMA number for Integrated Systems Division products  
(formerly Chipcom), use the following numbers.  
Country  
Telephone Number  
Fax Number  
(508) 787-3400  
No Fax  
U.S. and Canada (800) 724-2447  
Europe  
(44) (1442) 275860  
(508) 787-5296  
Asia Pacific  
(508) 787-3400  
Accessing the 3Com MIB  
The 3Com Management Information Base (MIB) for the Integrated Systems  
Division describes commands that enable you to manage 3Com  
SNMP-based products. The MIB is available over the Internet on an  
anonymous FTP server. Updates to these MIBs are released as new 3Com  
products are introduced.  
To access Internet versions:  
1. FTP to ftp.chipcom.com(151.104.9.65).  
2. Enter the login name anonymous.  
B - 4 ONline Ethernet 10BASE-T Module User’s Guide  
 
3. Enter your full Internet e-mail address as the password  
(for example, [email protected]).  
4. Change to the mib or schema directory using the cd /pub/mibsor  
cd /pub/mibs/schemascommand.  
5. To view the 3Com MIB, OID, or schema entries, enter the dir  
command.  
To pause the display, press [CTRL-S].  
To continue the display, press [CTRL-Q].  
6. Copy the MIB, OID, or schema files to your current directory using the  
appropriate command (for example, get chipcom.mib).  
7. To exit the FTP session, invoke the quitcommand.  
3Com Technical Publications  
If you have comments or questions on 3Com Integrated Systems Division  
Technical Publicationsdocuments, please contact the TechnicalPublications  
group by FAX (508) 229-1551.  
Technical Support B - 5  
 
 
Index  
Numerics  
D
3Com Bulletin Board Service (3ComBBS), B-3 Dip Switch Settings  
Channel Select, 1-8, 1-9  
Crossover Mode, 1-6, 1-7  
Link Integrity, 1-9, 1-10  
Port Status, 1-5  
A
Audience of Manual, xi  
Squelch Mode, 1-7, 1-8  
Dip Switches, 1-4  
B
Backbone  
Fiber Medium, 2-2  
bulletin board service, B-3  
F
FCC notice, ii  
Features, 1-1, 1-2  
Fiber Link Distances, 2-5  
Front Panel Indicators  
Activity LEDs, 1-2, 1-4  
Status Indicators, 1-2  
Status LEDs, 1-4  
C
Cable Types  
Shielded Twisted Pair, 1-1  
Unshielded Twisted Pair, 1-1  
Cabling  
Connectors, A-3, A-4  
Fiber Backbone, 2-7, 2-8, 2-10  
Redundant Links, 2-13  
Twisted Pair Backbone, 2-11  
Twisted Pair Connections, 2-10  
Wire Types, A-4  
I
Installation  
Cabling, 3-4  
Installing The Module, 3-3, 3-4  
Configuration Rules  
L
Fiber Backbone, 2-9  
Configuration Rules  
LAN Product Equivalent Distances, 2-6  
Fiber Backbone, 2-7, 2-8  
General, 2-2, 2-3, 2-5  
Twisted Pair Backbone, 2-11, 2-12  
Link Distances  
Configuration Rules, 1-1  
Index 1  
 
U
M
Unshielded Twisted Pair, 2-8, 2-10, 2-11  
MIB, B-4  
V
N
VDE compliance, ii  
network supplier support, B-2  
W
O
Wire Types, 1-1  
ONline Controller Module, 1-10  
ONline Ethernet Management Module, 1-11,  
1-12  
on-line technical services, B-1  
P
Patch Panels, 2-14  
R
Redundancy, 2-13  
returning products for repair, B-4  
S
Shielded Twisted Pair, 2-10, 2-12  
SNMP Commands, B-4  
Star Topology, 2-3  
T
Technical Assistance, 4-6  
Technical Support, 4-6, B-1  
Troubleshooting  
Port Activity LEDs, 4-5  
Port Status LEDs, 4-1, 4-3, 4-4  
Technical Assistance, 4-6  
Twisted Pair  
Cables, A-4, A-5  
Connections, A-5  
Connectors, A-3, A-4  
2 Index  
 

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