Cabletron Systems SEHI-22FL User Manual

SEHI-22FL

INTELLIGENT STACKABLE HUB

USER’S GUIDE

NOTICE

Cabletron Systems reserves the right to make changes in specifications and other information
contained in this document without prior notice. The reader should in all cases consult Cabletron
Systems to determine whether any such changes have been made.

The hardware, firmware, or software described in this manual is subject to change without notice.
IN NO EVENT SHALL CABLETRON SYSTEMS BE LIABLE FOR ANY INCIDENTAL,

INDIRECT, SPECIAL, OR CONSEQUENTIAL DAMAGES WHATSOEVER (INCLUDING BUT
NOT LIMITED TO LOST PROFITS) ARISING OUT OF OR RELATED TO THIS MANUAL OR
THE INFORMATION CONTAINED IN IT, EVEN IF CABLETRON SYSTEMS HAS BEEN
ADVISED OF, KNOWN, OR SHOULD HAVE KNOWN, THE POSSIBILITY OF SUCH
DAMAGES.



Copyright 1996 by Cabletron Systems, Inc., P.O. Box 5005, Rochester, NH 03866-5005
All Rights Reserved
Printed in the United States of America

Order Number: 9031652-01 April 1996

SPECTRUM, LANVIEW, MicroMMAC
Manager, EPIM, EPIM-A, EPIM-F1, EPIM-F2, EPIM-F3, EPIM-T, EPIM-X, FOT-F, FOT-F3
HubSTACK, SEH, SEHI

All other product names mentioned in this manual may be trademarks or registered trademarks of
their respective companies.

, and

TMS-3

Printed on Recycled Paper

, and

BRIM

are registered trademarks and

are trademarks of Cabletron Systems, Inc.

Element

,

SEHI User’s Guide i

Notice

FCC NOTICE

This device complies with Part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.

NOTE:

This equipment has been tested and found to comply with the limits for a Class A digital
device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable
protection against harmful interference when the equipment is operated in a commercial environment.
This equipment uses, generates, and can radiate radio frequency energy and if not installed in
accordance with the operator’s manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause interference in which case the user
will be required to correct the interference at his own expense.

WARNING:

party responsible for compliance could void the user’s authority to operate the equipment.

Changes or modifications made to this device which are not e xpressly appro v ed by the

DOC NOTICE

This digital apparatus does not exceed the Class A limits for radio noise emissions from digital
apparatus set out in the Radio Interference Regulations of the Canadian Department of
Communications.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables
aux appareils numériques de la class A prescrites dans le Règlement sur le brouillage radioélectrique
édicté par le ministère des Communications du Canada.

VCCI NOTICE

This equipment is in the 1st Class Category (information equipment to be used in commercial and/or
industrial areas) and conforms to the standards set by the Voluntary Control Council for Interference
by Information T echnology Equipment (VCCI) aimed at preventing radio interference in commercial
and/or industrial areas.

Consequently, when used in a residential area or in an adjacent area thereto, radio interference may be
caused to radios and TV receivers, etc.

Read the instructions for correct handling.

ii SEHI User’s Guide

Notice

CABLETRON SYSTEMS, INC. PROGRAM LICENSE AGREEMENT

IMPORTANT:

This document is an agreement between you, the end user, and Cabletron Systems, Inc. (“Cabletron”)
that sets forth your rights and obligations with respect to the Cabletron software program (the
“Program”) contained in this package. The Program may be contained in firmware, chips or other
media. BY UTILIZING THE ENCLOSED PRODUCT, YOU ARE AGREEING TO BECOME
BOUND BY THE TERMS OF THIS AGREEMENT, WHICH INCLUDES THE LICENSE AND
THE LIMITATION OF WARRANTY AND DISCLAIMER OF LIABILITY. IF YOU DO NOT
AGREE TO THE TERMS OF THIS AGREEMENT, PROMPTLY RETURN THE UNUSED
PRODUCT TO THE PLACE OF PURCHASE FOR A FULL REFUND.

Before utilizing this product, carefully read this License Agreement.

CABLETRON SOFTWARE PROGRAM LICENSE

1. LICENSE
package subject to the terms and conditions of this License Agreement.

You may not copy, reproduce or transmit any part of the Program except as permitted by the
Copyright Act of the United States or as authorized in writing by Cabletron.

2. OTHER RESTRICTIONS. You may not reverse engineer, decompile, or disassemble the
Program.

3. APPLICABLE LA W. This License Agreement shall be interpreted and governed under the laws
and in the state and federal courts of New Hampshire. You accept the personal jurisdiction and
venue of the New Hampshire courts.

. You have the right to use only the one (1) copy of the Program provided in this

EXCLUSION OF WARRANTY AND DISCLAIMER OF LIABILITY

1. EXCLUSION OF
writing, Cabletron makes no warranty, expressed or implied, concerning the Program (including
its documentation and media).

CABLETRON DISCLAIMS ALL WARRANTIES, OTHER THAN THOSE SUPPLIED TO
YOU BY CABLETRON IN WRITING, EITHER EXPRESSED OR IMPLIED, INCLUDING
BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE, WITH RESPECT TO THE PROGRAM, THE
ACCOMP ANYING WRITTEN MA TERIALS, AND ANY A CCOMP ANYING HARDWARE.

2. NO LIABILITY FOR CONSEQUENTIAL DAMAGES. IN NO EVENT SHALL
CABLETRON OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER
(INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS,
PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, SPECIAL,
INCIDENTAL, CONSEQUENTIAL, OR RELIANCE DAMAGES, OR OTHER LOSS)
ARISING OUT OF THE USE OR INABILITY TO USE THIS CABLETRON PRODUCT,
EVEN IF CABLETRON HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES. BECAUSE SOME STATES DO NOT ALLOW THE EXCLUSION OR
LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES, OR
ON THE DURATION OR LIMITATION OF IMPLIED WARRANTIES, IN SOME
INSTANCES THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO
YOU.

WARRANTY. Except as may be specifically provided by Cabletron in

SEHI User’s Guide iii

Notice

UNITED STATES GOVERNMENT RESTRICTED RIGHTS

The enclosed product (a) was developed solely at private expense; (b) contains “restricted computer
software” submitted with restricted rights in accordance with Section 52227-19 (a) through (d) of the
Commercial Computer Software - Restricted Rights Clause and its successors, and (c) in all respects
is proprietary data belonging to Cabletron and/or its suppliers.

For Department of Defense units, the product is licensed with “Restricted Rights” as defined in the
DoD Supplement to the Federal Acquisition Regulations, Section 52.227-7013 (c) (1) (ii) and its
successors, and use, duplication, disclosure by the Government is subject to restrictions as set forth in
subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at

252.227-7013. Cabletron Systems, Inc., 35 Industrial Way, Rochester, New Hampshire 03867-0505.

iv SEHI User’s Guide

CONTENTS

CHAPTER 1 INTRODUCTION

1.1 Using This Manual.......................................................................1-1

1.2 Document Conventions...............................................................1-2

1.3 Getting Help.................................................................................1-3

1.4 Related Manuals..........................................................................1-3

CHAPTER 2 SEHI FEATURES AND OPTIONS

2.1 SEHI Overview............................................................................2-2

2.2 SEHI Features............................................................................. 2-2

2.3 Stackable Capabilities.................................................................2-3

2.4 Remote Network Management Capabilities................................2-3

2.5 Optional Features........................................................................ 2-4

CHAPTER 3 INSTALLATION REQUIREMENTS AND

SPECIFICATIONS

3.1 Cable Specifications.................................................................... 3-1

3.1.1 HubSTACK Interconnect Cable Requirements............... 3-2

3.1.2 10BASE-FL Fiber Optic Network Requirements............. 3-2

3.1.3 10BASE-T UTP and STP Cable Specifications..............3-3

3.2 Network Port Specifications.........................................................3-4

3.3 COM Port Requirements.............................................................3-5

3.4 Transceiver Requirements ..........................................................3-5

3.5 Operating Specifications..............................................................3-6

3.6 Power Supply Requirements....................................................... 3-7

3.7 Environmental Requirements......................................................3-8

3.8 Agency Approvals........................................................................3-8

3.8.1 Safety.............................................................................. 3-8

3.8.2 Immunity ......................................................................... 3-8

3.8.3 Emission ......................................................................... 3-8

3.9 Physical Specifications................................................................ 3-8

SEHI User’s Guide v

Contents

CHAPTER 4 INSTALLATION

4.1 Unpacking the SEHI.....................................................................4-1

4.2 Pre-installation Test .....................................................................4-2

4.3 Installing the SEHI .......................................................................4-2

4.3.1 Tabletop or Shelf Installation...........................................4-3

4.3.2 Rackmount Installation....................................................4-4

4.3.3 Stacking the SEHI...........................................................4-6

4.4 Connecting the SEHI to the Power Source..................................4-8

4.5 Adding/Replacing EPIMs .............................................................4-9

CHAPTER 5 CONNECTING TO THE NETWORK

5.1 Connecting the SEHI to the Network ...........................................5-1

5.1.1 Connecting Network Ports...............................................5-1

5.1.2 Connecting a UTP Segment to an EPIM-T .....................5-4

5.1.3 Connecting a Fiber Segment to an EPIM-F1/F2/F3........5-5

5.1.4 Connecting a Thin Coaxial Segment to an EPIM-C........5-8

5.1.5 Connecting an AUI Cable to an EPIM-A .........................5-9

5.1.6 Connecting an AUI Cable to an EPIM-X .......................5-11

5.2 FInishing the Installation ............................................................5-12

CHAPTER 6 TROUBLESHOOTING

6.1 Installation CheckOut...................................................................6-1

6.2 Using LANVIEW...........................................................................6-2

6.3 Using the RESET Button .............................................................6-4

6.4 Setting the NVRAM Switch ..........................................................6-5

CHAPTER 7 LOCAL MANAGEMENT

7.1 Local Management Keyboard Conventions.................................7-2

7.2 Management Terminal Setup.......................................................7-3

7.3 Accessing Local Management.....................................................7-6

7.4 The Feature Selection Screen .....................................................7-7

7.5 The Community Name Table Screen...........................................7-8

7.6 The Configuration Screen..........................................................7-10

7.7 The Trap Table Screen..............................................................7-14

7.8 The SNMP Tools Screen ...........................................................7-16

7.9 The Device Statistics Screen.....................................................7-20

vi SEHI User’s Guide

Contents

APPENDIX A EPIM INFORMATION

A.1 EPIM Specifications.....................................................................A-1

A.1.1 EPIM-T............................................................................A-1

A.1.2 EPIM-F1 and EPIM-F2....................................................A-2

A.1.3 EPIM-F3..........................................................................A-3

A.1.4 EPIM-C............................................................................A-4

A.1.5 EPIM-A and EPIM-X (AUI Port) ......................................A-5

APPENDIX B IMAGE FILE DOWNLOAD USING OIDs

B.1 Setting up a UNIX Workstation as a TFTP Server ......................B-2

B.2 Standard TFTP Download...........................................................B-3

INDEX

SEHI User’s Guide vii

CHAPTER 1

INTRODUCTION

Welcome to the Cabletron Systems

Hub User’s Guide

reference information for the SEHI-22FL.

NOTE

The term SEHI (Stackable Ethernet Hub with Intelligence) is
used throughout this manual when describing the features and
functions of the SEHI-22FL.

. This manual provides installation instructions and

SEHI-22FL Intelligent Stackable

1.1 USING THIS MANUAL

Read through this manual to gain an understanding of the features and
capabilities of the SEHI. A general knowledge of Ethernet and IEEE

802.3 type data communications networks and their physical layer

components is helpful when installing the SEHI.
Chapter 1,

document conventions, provides getting help information and concludes
with a list of related manuals.

Chapter 2,
and provides information about available options including EPIMs
(Ethernet Port Interface Modules) and HubSTACK interconnect cables.

Chapter 3,
installation requirements, network guidelines, and SEHI operating
specifications.

Introduction

SEHI Features and Options

Installation Requirements and Specifications

, outlines the contents of this manual, describes

, details the features of the SEHI

, describes

Chapter 4,
stackable or standalone hub.

Chapter 5,
SEHI to the network using the various media types.

Chapter 6,
to troubleshoot network problems.

SEHI User’s Guide 1-1

Installation

Connecting to the Network

Troubleshooting

, contains instructions for installing the SEHI as a

, explains how to connect the

, describes how to use the LANVIEW LEDs

Chapter 1:

Introduction

Chapter 7,

Local Management

, describes how to use SEHI Local

Management screens and the available commands.
Appendix A,

EPIM Information

, provides specifications, cabling

information, and switch settings for the Ethernet Port Interface Modules.
Appendix B,

Image File Download Using OIDs

, provides instructions
for setting up a TFTP server and downloading image files to the SEHI by
setting specific MIB OID strings.

1.2 DOCUMENT CONVENTIONS

The following conventions are used throughout this document:

Note

NOTE

TIP

symbol. Calls the reader’s attention to any item of

information that may be of special importance.

Tip

symbol. Conveys helpful hints concerning procedures or

actions.

Caution

damage to the equipment.

!

CAUTION

Warning

equipment damage, personal injury or death.

1-2 SEHI User’s Guide

symbol. Contains information essential to avoid

symbol. Warns against an action that could result in

Getting Help

1.3 GETTING HELP

If you need additional support related to this device, or if you have any
questions, comments, or suggestions concerning this manual, contact
Cabletron Systems Technical Support:

By phone [phone]

A.M

Monday – Friday; 8
By CompuServe GO CTRON from any ! prompt
By Internet mail [e-mail]
By FTP ctron.com (134.141.197.25)

Login
Password

anonymous

your email address

Before calling Cabletron Systems Technical Support, have the following
information ready:

• A description of the failure

• A description of any action(s) already taken to resolve the problem

(e.g., changing mode switches, rebooting the unit, etc.)

• A description of your network environment (layout, cable type, etc.)

. – 8 P.M. Eastern Time

• Network load and frame size at the time of trouble (if known)

• The serial and revision numbers of all Cabletron Systems products in

the network

• The device history (i.e., have you returned the device before, is this a

recurring problem, etc.)

• Any previous Return Material Authorization (RMA) numbers

1.4 RELATED MANUALS

Use the Cabletron Systems
supplement the procedures and other technical data provided in this
manual. The procedures contained in the

User’s Guide

are referenced where appropriate, but not repeated in this

manual.

SEHI User’s Guide 1-3

SEH-22FL Stackable Hub User’s Guide

SEH-22FL Stackable Hub

to

CHAPTER 2

SEHI FEATURES AND OPTIONS

This chapter provides an overview of the SEHI-22FL and contains
sections detailing features and available options.

NOTE

HubSTACK
SEHI-22FL

The term SEHI (Stackable Ethernet Hub with Intelligence) is
used throughout this manual when describing features and
functions of the SEHI-22FL.

FRONT VIEW

10BASE-FL HUB WITH LANVIEW

PWR

CPU

RCV
LNK

COM

CLN

12 11 10 9 8 7 6 5 4 3 2 1

RESET

Port Status LEDs
System LEDs
COM Port
RESET Button

Power Supply
ON/OFF Switch

®

SECURE

REAR VIEW

RX

RX

TX

1112

RX

RX

TX

E
1

56

RX

TX

RX

TX

TX

10

9

RX

TX

RX

TX

TX

4

3

Network Ports 1-12

SEHI-22FL 100BASE-FL HUB WITH LANVIEW®

SEH INTERCONNECT

OUT

Interconnect Bus "OUT" Port

RX

RX

TX

TX

8

7

RX

RX

TX

TX

2

1

EPIM Slot

EPIM 1

165212

Figure 2-1 Front and Rear Views of the SEHI-22FL

SEHI User’s Guide 2-1

Chapter 2:

SEHI Features and Options

2.1 SEHI OVERVIEW

The SEHI-22FL is an intelligent repeating hub providing front panel ports
for network connections and a rear panel HubSTACK Interconnect Bus
port for stackable connections. The SEHI is designed to manage the
Cabletron Systems SEH series of non-intelligent stackable hubs.

The SEHI-22FL provides twelve 10BASE-FL ST-type fiber optic ports
and one EPIM (Ethernet Port Interface Module) port.

2.2 SEHI FEATURES

This section provides detailed information about SEHI features and
capabilities.

Repeater Functionality

The SEHI fully conforms to the IEEE 802.3 10BASE-FL specifications,
and provides the flexibility to connect networks using IEEE 802.3,
Ethernet Version 1 or Version 2 equipment. The SEHI transmits retimed
data packets, regenerates the preamble, extends fragments, and arbitrates
collisions.

The SEHI automatically partitions problem segments, and reconnects
repaired segments to the network. This feature minimizes the impact on
network operation resulting from a problem on one segment by isolating
the problem segment. Only devices on the problem segment are affected.
When the problem is solved, the SEHI automatically reconnects the
isolated segment to the network.

FLASH EEPROMs

The SEHI uses FLASH EEPROMs that allow the downloading of new
and updated firmware using Cabletron Systems SPECTRUM Element
Manager/Windows or any device using BOOTP or TFTP protocols.

LANVIEW LEDs

Cabletron Systems LANVIEW Status Monitoring and Diagnostics
System is a troubleshooting tool that helps in diagnosing power failures,
collisions, cable faults, and link problems. The LANVIEW LEDs are
conveniently located on the SEHI front panel.

2-2 SEHI User’s Guide

Stackable Capabilities

RESET Button

Resetting the hub with the front panel RESET button reboots the SEHI
and initializes the processor.

Local Management

Manage the SEHI and attached segments through Local Management on
the SEHI. Local Management provides full packet and error statistics for
the entire stack, individual device, or individual port. Access Local
Management by attaching a DEC VT320 terminal or a PC using VT320
emulation software to the SEHI RJ45 COM port.

2.3 STACKABLE CAPABILITIES

The SEHI intelligent hub is designed to manage the Cabletron Systems
series of SEH non-intelligent hubs. The SEHI serves as the logical “top”
of the stack. It manages all SEH hubs in the stack providing full packet
and error statistics for the entire stack, individual device, or individual
port.

Stack up to four SEH non-intelligent hubs with one SEHI using Cabletron
Systems external HubSTACK Interconnect cables. Stackable
configurations make it possible to maintain only one IEEE repeater hop
while providing up to 130 10BASE-T Ethernet ports. Add or remove hubs
from the stack without powering down.

2.4 REMOTE NETWORK MANAGEMENT

CAPABILITIES

Manage the SEHI remotely with any SNMP network management
system. Cabletron Systems offers the following remote management
packages:

• Cabletron Systems SPECTRUM

• Cabletron Systems SPECTRUM Element Manager/Windows

• Cabletron Systems Remote SPECTRUM Portable Management

Applications

• Third Party SNMP compliant Network Management Packages

SEHI User’s Guide 2-3

Chapter 2:

SEHI Features and Options

2.5 OPTIONAL FEATURES

The following features are not included with the SEHI, but are purchased
separately from Cabletron Systems.

Ethernet Port Interface Modules (EPIMs)

EPIMs enable the expansion of the network through a variety of media.
Cabletron Systems offers the EPIMs shown in Table 2-1.

Table 2-1 EPIMs

EPIM Media Type Connector

EPIM-A AUI DB15 (Female)
EPIM-C 10BASE2 Thin Coaxial BNC

EPIM-T
EPIM-X Standard T r ansceiver DB15 (Male)

EPIM-F1 Multimode Fiber SMA
EPIM-F2 Multimode Fiber ST
EPIM-F3 Single Mode Fiber ST

10BASE-T Unshielded Twisted
Pair

RJ45

HubSTACK Interconnect Cables

Stack hubs together with Cabletron Systems HubSTACK Interconnect
cables. Table 2-2 lists the part number and the application for each cable.

Table 2-2 HubSTACK Interconnect Cables

P/N Description Application

9380110

9380111

12" HubSTACK
Interconnect Cable

18" HubSTACK
Interconnect Cable

SEH to SEH connections.

SEHI to SEH connections.

Rack Mount Hardware

The SEHI can be installed in a 19-inch rack. Cabletron offers an
accessory package that includes brackets and mounting screws. The part
number for the accessory package is SEHI-ACCY-KIT.

2-4 SEHI User’s Guide

CHAPTER 3

INSTALLATION REQUIREMENTS AND

SPECIFICATIONS

This chapter describes cabling requirements, network guidelines, and
operating specifications for the SEHI.

The network must meet the requirements and conditions
specified in this chapter to obtain satisfactory performance from

!

CAUTION

The network must meet the requirements and conditions specified in this
chapter to obtain satisfactory performance from this equipment. Failure to
follow these guidelines can result in poor network performance.

3.1 CABLE SPECIFICATIONS

The SEHI-22FL network ports support 10BASE-FL Multimode Fiber
Optic cabling.

this equipment. Failure to follow these guidelines can result in
poor network performance.

Ethernet Port Interface Modules (EPIMs) expand a network using
Unshielded Twisted Pair (UTP), Shielded Twisted Pair (STP), Multimode
Fiber Optic, Single Mode Fiber Optic, or Thin Coaxial cabling. For
information concerning EPIMs, refer to Appendix A.

The rear panel Interconnect Bus port supports Cabletron Systems
HubSTACK Interconnect cables for stackable applications.

T ak e care in planning and preparing the network cabling and connections.
The quality of the connections and the length of cables are critical factors
in determining the reliability of the network. The following sections
provide the specifications for each media type.

SEHI User’s Guide 3-1

Chapter 3: Installation Requirements and Specifications

3.1.1 HubSTACK Interconnect Cable Requirements

Attach the SEHI to modules in the stack with the SEHI HubSTACK
Interconnect cable available only from Cabletron Systems. Refer to
Chapter 1 for cable part numbers. The cable attaches to the SEHI rear
panel bus port.

The rear panel of the SEHI has an Interconnect Bus Out port (male
connector) to stack SEH non-intelligent hubs together. Stack up to four
SEH hubs together with one SEHI.

3.1.2 10BASE-FL Fiber Optic Network Requirements

Table 3-1 shows Multimode Fiber Optic Cable specifications for the
SEHI-22FL.

Table 3-1 Multimode Fiber Optic Cable Specifications

Cable Type Attenuation Maximum Cable Length

50/125 µm 13.0 dB or less Maximum fiber optic cable length is 2

62.5/125 µm 16.0 dB or less
100/140 µm 19.0 dB or less

km (2187.2 yds). However, IEEE 802.3
specifications allow for a maximum of 1
km (1093.6 yds).

Attenuation

T est the fiber optic cable with a fiber optic attenuation test set adjusted for
an 850 nm wavelength. This test verifies that the signal loss in a cable is
within an acceptable level. Table 3-1 shows the attenuation for each
Multimode cable type.

Fiber Optic Budget and Propagation Delay

Determine the maximum fiber optic cable length by calculating the fiber
optic budget delay and total network propagation before the fiber optic
cable runs are incorporated into a network design.

Fiber optic budget is the combination of the optical loss due to the fiber
optic cable, in-line splices, and fiber optic connectors.

Propagation delay is the amount of time it takes data to travel from the
sending device to the receiving device. Total propagation delay allowed
for the network is 25.6 µs (51.2 µs roundtrip). If the total propagation
delay between any two nodes on the network exceeds 25.6 µs, then use
bridges.

3-2 SEHI User’s Guide

Cable Specifications

3.1.3 10BASE-T UTP and STP Cable Specifications

The devices and 10BASE-T Twisted Pair Segments connected to an SEHI
EPIM-T module must meet the IEEE 802.3 10BASE-T specifications
shown below:

Length

The IEEE 802.3 10BASE-T standard requires that 10BASE-T devices
transmit over a 100 meter (328 foot) link using 22-24 AWG Unshielded
Twisted Pair (UTP) wire. However, cable quality largely determines the
maximum link length. With high quality, low attenuation cable, link
lengths of up to 200 meters are achievable. Cable delay limits the
maximum link length to 200 meters, regardless of the cable type.

Insertion Loss

The maximum insertion loss allowed for a 10BASE-T link is 11.5 dB at
all frequencies between 5.0 and 10 MHz. This includes the attenuation of
the cables, connectors, patch panels, and reflection losses due to
impedance mismatches in the link segment.

Impedance

Cabletron Systems 10BASE-T Twisted Pair products work on twisted pair
cable with 75 to 165 ohms impedance. UTP cables typically have an
impedance of 85 to 110 ohms.

Shielded Twisted Pair (STP) cables, such as IBM Type 1 cable, are also
used. The impedance of IBM Type 1 cable is typically 150 ohms. Higher
impedance increases signal reflection, but because the cable is shielded,
signal reflection has little effect on the quality of the received signal due
to the lack of crosstalk between the shielded cable pairs.

Jitter

Intersymbol interference and reflections cause jitter in the bit cell timing,
resulting in data errors. A 10BASE-T link must not generate more than

5.0 ns of jitter. If the cable meets the impedance requirements for a
10BASE-T link, jitter should not be a concern.

Delay

The maximum propagation delay of a 10BASE-T link segment must not
exceed 1000 ns. This 1000 ns maximum delay limits the maximum link
segment length to no greater than 200 meters.

SEHI User’s Guide 3-3

Chapter 3: Installation Requirements and Specifications

Crosstalk

Crosstalk is caused by signal coupling between the different cable pairs
contained within a multi-pair cable bundle. 10BASE-T transceivers are
designed so that the user does not need to be concerned about cable
crosstalk, provided the cable meets all other requirements.

Noise

Noise is caused by either crosstalk or externally induced impulses.
Impulse noise may cause data errors if the impulses occur at very specific
times during data transmission. Generally , the user need not be concerned
about noise. If noise-related data errors are suspected, it may be necessary
to either reroute the cable or eliminate the source of the impulse noise.

Temperature

Multi-pair PVC 24 AWG cables typically have an attenuation of
8 dB to 10 dB/100 meters at 20°C (68°F). The attenuation of PVC
insulated cable varies significantly with temperature. At temperatures
greater than 40°C (104°F), Cabletron Systems recommends the use of
plenum-rated cables to ensure that cable attenuation remains within
specification.

3.2 NETWORK PORT SPECIFICATIONS

The SEHI-22FL provides ST-type ports for 10BASE-FL Multimode Fiber
Optic cabling. Figure 3-1 shows the network ports.

RX

RX

RX

TX

TX

1112

RX

RX

TX

TX

56

Figure 3-1 SEHI-22FL Network Ports

3-4 SEHI User’s Guide

RX

RX

RX

TX

TX

10

9

RX

TX

TX

4

3

RX

TX

TX

8

7

RX

RX

TX

TX

2

1

09162_04

COM Port Requirements

3.3 COM PORT REQUIREMENTS

The RJ45 COM port supports access to a Local Management Console.
The Console port supports a Digital Equipment Corporation, VT320
terminal or PC emulation of the VT320 terminal. Figure 3-2 shows the
pinouts for the RJ45 COM port.

1 2 3 4 5 6 7 8

COM

1. Transmit Data

2. Data Carrier Detect

3. Data Set Ready

4. Receive Data

Figure 3-2 COM Port Pinouts

5. Signal Ground

6. Data Terminal Ready

7. Request To Send

8. Clear To Send

165201

3.4 TRANSCEIVER REQUIREMENTS

When connecting an external network segment through a transceiver to
the SEHI with an EPIM-A, the following requirements must be met:

• The transceiver or Ethernet device to which the module is connected

must meet IEEE 802.3 standards, and/or Ethernet Version 1.0 or
Version 2.0 standards.

• The Signal Quality Error (SQE) test function on the transceiver must

be disabled when it is connected to a repeater or to an Ethernet Version

1.0 device. In addition, some Version 2.0 equipment does not support
the SQE test. Devices that do not support the SQE test interpret the
SQE test pulse as a collision.

SEHI User’s Guide 3-5

Chapter 3: Installation Requirements and Specifications

3.5 OPERATING SPECIFICATIONS

The operating specifications for the SEHI are described in this section.
Cabletron Systems reserves the right to change these specifications at any
time without notice.

System Specifications

Operating System Memory: 1.5 MB
Internal Processor: Intel i960 operating at 16 MHz
Ethernet Controller: National Semiconductor DP83916
Non-Volatile RAM: 32 KB with battery back-up
EPROM: 64 KB
FLASH MEMORY: 1 MB

Delay Time (Start of Packets) Specifications

Twisted Pair to EPIM-A: 1.10 ms
Twisted Pair to Twisted Pair: 1.00 ms
EPIM-A to Twisted Pair: 1.00 ms

Delay Times (JAM) Specifications

Twisted Pair to EPIM-A: 960 ns

Preamble Specifications

Input: Minimum of 40 bits required
Output: 64 bits min. (last 2 bits are 1,1)

3-6 SEHI User’s Guide

Power Supply Requirements

JAM Output Specifications

Collisions are propagated through the network using the J AM signal of an
alternating pattern of 1’s and 0’s in accordance with 802.3 specifications
for a repeater unit.

Fragment Extension Specifications

Fragments are extended to a minimum of 96 bits using the JAM [1,0].

Fault Protection Specifications

Each segment disconnects itself from the other segments if 32 consecutiv e
collisions occur, or if the collision detector of a segment is on for longer
than approximately 110 µs. This fault protection resets automatically after
one packet is transmitted/received onto the fault protected segment
without causing a collision.

3.6 POWER SUPPLY REQUIREMENTS

The SEHI has a universal power supply. The input power requirements
are listed in Table 3-2.

Table 3-2 Power Requirements

Model Voltage Range Frequency Range

SEHI-22FL

100–125 Vac
or 200–250 Vac

50/60 Hz

The power supply has two outputs of +5 Vdc and +12 Vdc. The maximum
output power is 40 W and the minimum efficiency is 65% under all
conditions of the line at full load. The minimum and maximum load
currents from each output are listed in Table 3-3.

Table 3-3 Power Supply Output Specifications

Output Min. Load Max. Load Max Power

+5 Vdc 0.75 A 4 A 20 W
+12 Vdc 0.00 A 2 A 24 W

SEHI User’s Guide 3-7

Chapter 3: Installation Requirements and Specifications

3.7 ENVIRONMENTAL REQUIREMENTS

The environmental requirements for the SEHI are detailed in this section.
Operating T emperature: 5°C to 40°C (41°F to 104°F)
Storage T emperature: -30°C to 90°C (-22°F to 194°F)
Operating Humidity: 5% to 95% (non-condensing)

3.8 AGENCY APPROVALS

The Safety, Immunity, and Emission approvals for the SEHI are detailed
in this section.

3.8.1 Safety

This unit meets the safety requirements of UL 1950, CSA C22.2 No. 950,
IEC 950, and EN 60950.

3.8.2 Immunity

This unit meets the immunity requirements of EN 50082-1 including
IEC 801-2 (ESD), IEC 801-3 (Radiated Susceptibility),
and IEC 801-4 (EFT/B).

3.8.3 Emission

This unit meets the emission requirements of FCC Part 15 Class A,
EN 55022 Class A, and VCCI Class I.

3.9 PHYSICAL SPECIFICATIONS

This section details the physical specifications for the SEHI.
Dimensions (H x W x D): (7.2 cm x 43.6 cm x 34.6 cm)

(2.8 in x 17.0 in x 13.5 in)

Weight (Unit): 3 kg (6.5 lb)

3-8 SEHI User’s Guide

CHAPTER 4

INSTALLATION

This chapter outlines the procedure for attaching the SEHI to the network
as a stackable or standalone device. Ensure that the network meets the
guidelines and requirements outlined in Chapter 3, Installation
Requirements and Specifications, before installing the SEHI.

Failure to follow installation instructions may result in an
electrical shock hazard.

4.1 UNPACKING THE SEHI

Unpack the SEHI as follows:

1. Remove the shipping material covering the SEHI in the shipping box.

2. Carefully remove the SEHI from the shipping box and set it aside to

prevent damage.

3. Visually inspect the SEHI. If there are any signs of damage, contact

Cabletron Systems Technical Support immediately.

4. Read the SEHI Release Notes included in the shipping box.

NOTE

SEHI User’s Guide 4-1

Cabletron Systems includes a 3-1/2" disk with the SEHI that
contains a backup copy of the SEHI Flash Firmware Image
File. Download the file to the SEHI if the existing image
becomes corrupted.

Chapter 4: Installation

4.2 PRE-INSTALLATION TEST

The SEHI is equipped with an NVRAM reset switch (Figure 4-1) located
behind the grillwork on the side of the hub. Ensure that this switch is in
the DOWN position by looking in through the grillwork on the right side
of the hub. If the switch is UP, move it into the DOWN position with a
non-metallic tool. Do not remove the chassis cover to perform this
operation. Leaving the switch in the UP position results in user-installed
parameters such as IP address and Community Names being cleared from
NVRAM whenever the SEHI loses power and/or is reset. See Chapter 6,
Section 6.4, for detailed instructions on setting the NVRAM switch.

Rear of Chassis

NVRAM Switch located behind grating

09162_05

Figure 4-1 NVRAM Switch Location

4.3 INSTALLING THE SEHI

The SEHI may be installed on a tabletop or shelf, or in a 19-inch rack, and
configured as a standalone or stacked hub.

Refer to Section 4.3.1 for information concerning a tabletop or shelf
installation. Section 4.3.2 describes the rackmount installation.

4-2 SEHI User’s Guide

Installing the SEHI

4.3.1 Tabletop or Shelf Installation

This section provides guidelines for installation on a tabletop or shelf.
Tabletop and shelf installations must be within reach of the network
cabling and meet the requirements listed below:

• A single phase grounded power receptacle that meets the power supply

requirements listed in Chapter 3 under Power Supply Requirements
must be located within seven feet of the location.

• In a shelf installation, the shelf must be able to support 30 pounds of

static weight for each device in the stack.

• Maintain a temperature of between 5°C (41°F) and 40°C (104°F) at

the site with fluctuations of less than 10°C (18°F) per hour.

For a tabletop or shelf installation, locate the SEHI within seven feet of its
power source and with an unrestricted free surface area as shown in
Figure 4-2.

In order to allow for proper cooling, there must be a two-inch
clearance on either side and the back of the unit.

!

CAUTION

21 IN.

®

SECURE

RX

RX

E
1

RX

RX

RX

TX

RX

TX

TX

TX

RX

TX

TX

1112

10

789

RX

RX

RX

TX

RX

TX

TX

TX

RX

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56

4

EPIM 1

123

6 IN.

18 IN.

HubSTACK
SEHI-22FL

RESET

10BASE-FL HUB

PWR
CPU
CLN

COM

WITH

LANVIEW

RCV

LNK

12 11 10 9 8 7 6 5 4 3 2 1

7 FT

0165203

Figure 4-2 Tabletop or Shelf Installation

If the installation requires that the SEHI is to be stacked, proceed to
Section 4.3.3. Otherwise, continue by connecting power as described in
Section 4.4.

SEHI User’s Guide 4-3