Cabletron Systems SEH-22 User manual

SEH-22 AND SEH-24 10BASE-T
STACKABLE HUB
USER’S GUIDE
CABLETRON SYSTEMS, P. O. Box 5005, Rochester, NH 03866-5005
SEH Book Page 1 Tuesday, March 19, 1996 4:12 PM

SEH USER’S GUIDE i
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 August 1995 by: Cabletron Systems, Inc. P.O. Box 5005, Rochester, NH 03866-5005
All Rights Reserved
Printed in the United States of America
Order Number: 9031491 August 1995
SPECTRUM , LANVIEW , and Remote LANVIEW are registered trademarks and EPIM-A ,
EPIM-C , EPIM-F1/F2/F3 , EPIM-T , EPIM-X , HubSTACK , MicroMMAC , SEHI and SEH are
trademarks of Cabletron Systems, Inc.
CHAMP is a trademark of AMP, Inc.
CompuServe is a registered trademark of CompuServe, Inc.
DEC , VT200 , VT300 and VT320 are trademarks of Digital Equipment Corporation.
Ethernet is a trademark of Xerox Corporation.
IBM is a registered trademark of International Business Machines Corporation.
ST is a registered trademark of American Telephone and Telegraph Company
UNIX is a trademark of Unix Systems Laboratories, Inc.
Windows is a registered trademark of Microsoft Corporation.
This electric hazard symbol appears in the SEH User’s Guide. Read all
instructions following this symbol. Failure to follow the instructions
appearing with this symbol could result in the presence of an electric
hazard which has the potential to cause injury.
Printed On Recycled Paper
SEH Book Page i Tuesday, March 19, 1996 4:12 PM

NOTICE
ii SEH USER’S GUIDE
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,pursuanttoPart15oftheFCCrules.Theselimitsaredesignedtoprovidereasonableprotection
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
thisequipmentinaresidentialareaislikelytocauseinterferenceinwhichcasetheuserwillberequired
to correct the interference at his own expense.
WARNING: Changes or modifications made to this device which are not expressly approved by the
party responsible for compliance could void the user’s authority to operate the equipment.
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 Technology 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.
SEH Book Page ii Tuesday, March 19, 1996 4:12 PM

NOTICE
SEH USER’S GUIDE iii
CABLETRON SYSTEMS, INC.
PROGRAM LICENSE AGREEMENT
IMPORTANT: Before utilizing this product, carefully read this License Agreement.
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.
CABLETRON SOFTWARE PROGRAM LICENSE
1. LICENSE. You have the right to use only the one (1) copy of the Program provided in this
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 LAW. 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.
SEH Book Page iii Tuesday, March 19, 1996 4:12 PM

NOTICE
iv SEH USER’S GUIDE
EXCLUSION OF WARRANTY
AND DISCLAIMER OF LIABILITY
1. EXCLUSION OF WARRANTY. Except as may be specifically provided by Cabletron in
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
YOUBYCABLETRONINWRITING,EITHEREXPRESSORIMPLIED,INCLUDINGBUT
NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABLITY AND FITNESS
FOR A PARTICULAR PURPOSE, WITH RESPECT TO THE PROGRAM, THE
ACCOMPANYING WRITTEN MATERIALS, AND ANY ACCOMPANYING
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 WARRANTEES IN SOME
INSTANCES THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO
YOU.
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., P.O. Box 5005, Rochester, New Hampshire 03866-5005.
SEH Book Page iv Tuesday, March 19, 1996 4:12 PM

SEH USER’S GUIDE v
TABLE OF CONTENTS
CHAPTER 1 INTRODUCTION
1.1 USING THIS MANUAL............................................................................1-1
1.2 GETTING HELP ......................................................................................1-2
1.3 SEH OVERVIEW.....................................................................................1-2
1.4 SEH FEATURES.....................................................................................1-3
1.5 STACKABLE CAPABILITIES ..................................................................1-4
1.6 OPTIONAL FEATURES ..........................................................................1-4
1.7 RELATED MANUALS..............................................................................1-6
CHAPTER 2 INSTALLATION
REQUIREMENTS/SPECIFICATIONS
2.1 CABLE SPECIFICATIONS......................................................................2-1
2.1.1 HubSTACK Interconnect Cable Requirements.........................2-1
2.1.2 10BASE-T UTP and STP Cable Specifications.........................2-2
2.2 NETWORK PORT SPECIFICATIONS ....................................................2-4
2.3 TRANSCEIVER REQUIREMENTS.........................................................2-4
2.4 OPERATING SPECIFICATIONS.............................................................2-5
CHAPTER 3 INSTALLATION
3.1 UNPACKING THE SEH...........................................................................3-1
3.2 INSTALLING THE SEH...........................................................................3-1
3.2.1 Tabletop or Shelf Installation.....................................................3-2
3.2.2 Rackmount Installation Requirements.......................................3-3
3.2.3 Attaching the Strain Relief Bracket............................................3-4
3.2.4 Rack Mounting the SEH............................................................3-5
3.2.5 Stacking the SEH......................................................................3-6
3.3 CONNECTING THE SEH TO THE POWER SOURCE...........................3-9
3.4 ADDING/REPLACING EPIMs .................................................................3-9
CHAPTER 4 CONNECTING TO THE NETWORK
4.1 CONNECTING THE SEH TO THE NETWORK ......................................4-1
4.1.1 Connecting Network Ports, SEH-22 and SEH-24 .....................4-1
4.1.2 Connecting a UTP Segment to an EPIM-T ...............................4-3
4.1.3 Connecting a Fiber Segment to an EPIM-F1/F2/F3..................4-4
4.1.4 Connecting a Thin-Net Segment to an EPIM-C ........................4-6
4.1.5 Connecting an AUI Cable to an EPIM-A ...................................4-8
4.1.6 Connecting an AUI Cable to an EPIM-X ...................................4-9
4.2 FINISHING THE INSTALLATION..........................................................4-10
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CONTENTS
vi SEH USER’S GUIDE
CHAPTER 5 TROUBLESHOOTING
5.1 INSTALLATION CHECK-OUT.................................................................5-1
5.2 USING LANVIEW ....................................................................................5-2
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-5
A.1.5 EPIM-A and EPIM-X (AUI Port)................................................ A-6
A.2 EPIM CABLE SPECIFICATIONS ........................................................... A-7
A.2.1 Multimode Fiber Optic Cable Specifications............................. A-7
A.2.2 Single Mode Fiber Optic Cable Specifications ......................... A-8
A.2.3 Thin-Net Network Requirements for the EPIM-C ..................... A-9
A.2.4 AUI Cable Requirements for the EPIM-A and EPIM-X........... A-10
INDEX
SEH Book Page vi Tuesday, March 19, 1996 4:12 PM

SEH USER’S GUIDE 1-1
CHAPTER 1
INTRODUCTION
Welcome to the Cabletron Systems SEH-22 and SEH-24 10BASE-T
Stackable Hubs User’s Guide . This manual provides installation
instructions and reference information for the SEH-22 and SEH-24.
1.1 USING THIS MANUAL
Read through this manual completely to familiarize yourself with its
content and to gain an understanding of the features and capabilities of
the SEH. A general working knowledge of Ethernet and IEEE 802.3 type
data communications networks and their physical layer components is
helpful when installing the SEH.
Chapter 1,
Introduction , outlines the contents of this manual, briefly
describes SEH features, and concludes with a list of related manuals.
Chapter 2,
Installation Requirements/Specifications , describes
installation requirements, network guidelines, and specifications.
Chapter 3,
Installation , contains instructions for installing the SEH as a
stackable or stand-alone hub.
Chapter 4,
Connecting to the Network , explains how to connect the SEH
to the network using the various media types.
Chapter 5,
Troubleshooting , describes how to use the LANVIEW LEDs
to troubleshoot network problems.
Appendix A,
EPIM Information , provides specifications, cabling
information, and switch settings for the Ethernet Port Interface Modules.
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CHAPTER 1: INTRODUCTION
1-2 SEH USER’S GUIDE
1.2 GETTING HELP
If you need additional support related to the Cabletron Systems SEH, or if
you have any questions, comments, or suggestions concerning this
manual, contact Cabletron Systems Technical Support:
By phone ..........................[phone]
Monday-Friday; 8am - 8pm Eastern Time
By CompuServe...............GO CTRON from any ! prompt
By Internet mail ...............[email protected]
By FTP.............................134.141.197.25
Login:
anonymous , Password: your email address
1.3 SEH OVERVIEW
The SEH-22 is a non-intelligent repeating hub that has 12 RJ45 ports and
one Ethernet Port Interface Module (EPIM) port on the front panel for
network connections while the SEH-24 has 24 RJ45 ports and two EPIM
ports on the front panel for network connections. Both models have two
rear panel HubSTACK Interconnect Bus ports for stackable connections.
Figure 1-1. Front and Rear Views of the SEH-22 and SEH-24
HubSTACK10BASE-T HUB WITH LANVIEW®
SEH-22
1491_1
SEH INTERCONNECT
OUT IN
EPIM-1
EPIM-2
PWR
MGMT
CLN E1
E2
RCV
LNK
RCV
LNK
24 22 20 18 16 14 12 246810
23 21 19 17 15 13 11 13579
2X4X6X8X10X12X
14X16X18X20X22X24X
1X3X5X7X9X11X13X15X17X19X21X23X
HubSTACK10BASE-T HUB WITH LANVIEW®
SEH-24
HubSTACK10BASE-T HUB WITH LANVIEW®
SEH-24
SEH INTERCONNECT
OUT IN
EPIM-1
PWR
MGMT
CLN E1
RCV
LNK
RCV
LNK
12 246810
11 13579
2X4X6X8X10X12X
1X3X5X7X9X11X
HubSTACK10BASE-T HUB WITH LANVIEW®
SEH-22
SEH Book Page 2 Tuesday, March 19, 1996 4:12 PM

SEH FEATURES
SEH USER’S GUIDE 1-3
Stack up to five SEH hubs using Cabletron Systems external HubSTACK
Interconnect cables. Manage the stack by using the Cabletron Systems
MicroMMAC or SEHI (Stackable Ethernet Hub with Intelligence). Up to
four SEH hubs can be stacked with one intelligent hub. Stackable
configurations make it possible to maintain only one IEEE repeater hop
while providing up to 130 Ethernet ports.
1.4 SEH FEATURES
Repeater Functionality
The SEH fully conforms to the IEEE 802.3 Repeater, AUI, and
10BASE-T specifications, and provides the flexibility to connect
networks using IEEE 802.3, Ethernet Version 1 or Version 2 equipment.
The SEH transmits re-timed data packets, regenerates the preamble,
extends fragments, and arbitrates collisions.
The SEH automatically partitions problem segments, and reconnects
repaired segments to the network. This feature minimizes the impact on
network operation by isolating the problem segment. Only devices on the
problem segment are affected. When the problem is solved, the SEH
automatically reconnects the isolated segment to the network.
Polarity Detection and Correction
Each twisted pair port on the SEH incorporates a Polarity Detection and
Correction feature that allows the SEH to pass data regardless of the
polarity of the twisted pair segment’s receive link. Cabletron does not
recommend operating in this condition. When this condition is
discovered, remove the segment from the network and wire it correctly to
reduce the potential for problems if equipment changes are made.
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
located on the front panel.
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CHAPTER 1: INTRODUCTION
1-4 SEH USER’S GUIDE
1.5 STACKABLE CAPABILITIES
The SEH is a non-intelligent hub designed to be managed by a Cabletron
Systems intelligent hub such as the SEHI or the MicroMMAC. Intelligent
hubs serve as the logical “top” of the stack. They manage all SEH hubs in
the stack, providing full packet and error statistics for the entire stack,
individual device, or individual port. Stack up to five SEH hubs for a
non-managed stack or one intelligent hub and up to four SEH hubs for a
managed stack. Hubs can be added or removed from the stack without
powering down the entire stack.
1.6 OPTIONAL FEATURES
The following features are not included with the SEH, but can be
purchased separately from Cabletron Systems.
Ethernet Port Interface Modules (EPIMs)
EPIMs enable the expansion of a network through a variety of media.
Cabletron offers the EPIMs shown in Table 1-1.
Table 1-1. EPIMs
EPIM MediaType Connector
EPIM-A 10BASE-5 AUI DB15 (Female)
EPIM-C 10BASE-2 Thin Coaxial BNC
EPIM-T 10BASE-T Unshielded Twisted Pair RJ45
EPIM-X Standard Transceiver DB15 (Male)
EPIM-F1 Multimode Fiber SMA
EPIM-F2 Multimode Fiber ST
EPIM-F3 Single Mode Fiber ST
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OPTIONAL FEATURES
SEH USER’S GUIDE 1-5
Table 1-2 lists the board revision requirements for EPIMs used in the
SEH-24. The board revision number is located on the EPIM’s printed
circuit board directly after the part number as shown in Figure 1-2.
Figure 1-2. EPIM Board Revision Number
Table 1-2. EPIM Board Revision Requirements
EPIM EPIM BOARD REVISION
EPIM-A Not Applicable
EPIM-C 05 or greater
EPIM-T 04 or greater
EPIM-X 02 or greater
EPIM-F1 05 or greater
EPIM-F2 05 or greater
EPIM-F3 02 or greater
CABLETRON SYSTEMS INC. PN 9000474 - 04
EPIM Board Revision
EPIM-T
1490_2
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CHAPTER 1: INTRODUCTION
1-6 SEH USER’S GUIDE
HubSTACK Interconnect Cables
Use Cabletron HubSTACK Interconnect cables to stack hubs together.
Table 1-3 lists the part number and application for each cable.
Rack Mount Capabilities
The SEH can be installed in a 19-inch rack. Cabletron offers an accessory
package that includes the brackets, a strain relief for cable management
and mounting screws. The part number for the accessory package is
SEH-ACCY-KIT. See Chapter 3,
Installation , for complete rack
mounting instructions.
1.7 RELATED MANUALS
Use the following Cabletron Systems manuals to supplement the
procedures and other technical data provided in this manual. The
procedures contained in these manuals are referenced where appropriate,
rather than repeated in this manual.
SEHI-22 and SEHI-24 10BASE-T Intelligent Hub User’s Guide
MicroMMAC-22E/24E and MicroMMAC-32E/34E User’s Guide
Table 1-3. HubSTACK Interconnect Cables
P/N Description Application
9380110 12" HubSTACK
Interconnect Cable SEH to SEH connections.
9380111 18" HubSTACK
Interconnect Cable SEHI or MicroMMAC to SEH connections.
SEH Book Page 6 Tuesday, March 19, 1996 4:12 PM

SEH USER’S GUIDE 2-1
CHAPTER 2
INSTALLATION
REQUIREMENTS/SPECIFICATIONS
This chapter describes network guidelines, power requirements, and
operating specifications for the SEH. Be sure to read this chapter before
you install the SEH. The network must meet the requirements and
conditions specified in this chapter to obtain satisfactory performance
from this equipment. Failure to follow these guidelines could result in
poor network performance.
2.1 CABLE SPECIFICATIONS
The SEH-22 and SEH-24 network ports support Shielded Twisted Pair
(STP) and Unshielded Twisted Pair (UTP) cabling.
Ethernet Port Interface Modules (EPIMs) expand a network using UTP,
STP, Multimode Fiber Optic, Single Mode Fiber Optic, or Thin Coaxial
cabling. For information concerning EPIMs, refer toAppendix A. The
rear panel Interconnect Bus Ports support Cabletron Systems HubSTACK
Interconnect cables for stackable applications.
Take care in planning and preparing the cabling and connections for the
network. The quality of the connections and the length of cables are
critical factors in determining the reliability of your network. The
following sections describe specifications for each media type.
2.1.1 HubSTACK Interconnect Cable Requirements
Connect units in the stack with HubSTACK Interconnect cables. Refer to
Chapter 1 for cable part numbers. The cables attach to the SEH rear panel
bus ports.
The rear panel of the SEH has an SEH Interconnect Bus Out Port (male
connector) and an SEH Interconnect Bus In Port (female connector). The
bus supports five stackable devices.
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CHAPTER 2: INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-2 SEH USER’S GUIDE
2.1.2 10BASE-T UTP and STP Cable Specifications
The devices and 10BASE-T Twisted Pair Segments connected to the SEH
10BASE-T Twisted Pair Network Ports and 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 wire. However, cable quality largely determines maximum
link length. With high quality, low attenuation cable, link lengths of up to
200 meters are achievable. Cable delay limits maximum link length to
200 meters, regardless of cable type.
Insertion Loss
The maximum insertion loss allowed for a 10BASE-T link is 11.5 dB at
all frequencies between 5 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. Unshielded twisted pair cables
typically have an impedance of between 85 to 110 ohms.
Shielded twisted pair cables, such as IBM Type 1 cable, can also be used.
The impedance of IBM Type 1 cable is typically 150 ohms. This increases
the signal reflection caused by the cable, but because the cable is shielded,
this signal reflection has little effect on the received signal’s quality 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.
SEH Book Page 2 Tuesday, March 19, 1996 4:12 PM

CABLE SPECIFICATIONS
SEH USER’S GUIDE 2-3
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.
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 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 recommends the use of plenum-rated cables to
ensure that cable attenuation remains within specification.
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CHAPTER 2: INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-4 SEH USER’S GUIDE
2.2 NETWORK PORT SPECIFICATIONS
The SEH-22 and SEH-24 network ports use shielded RJ45 connectors
that support both STP and UTP cabling. Figure 2-1 shows the RJ45
pinouts.
Figure 2-1. RJ45 Network Ports
2.3 TRANSCEIVER REQUIREMENTS
When connecting an external network segment via a transceiver to the
SEH with an EPIM-A, the following requirements must be met:
• The transceiver or Ethernet Device to which the module will be
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.
1 2 3 4 5 6 7 8
1. Receive + 5. Not Used
2. Receive - 6. Transmit -
3. Transmit + 7. Not Used
4. Not Used 8. Not Used
5X 3X 1X
1490_3
SEH Book Page 4 Tuesday, March 19, 1996 4:12 PM

OPERATING SPECIFICATIONS
SEH USER’S GUIDE 2-5
2.4 OPERATING SPECIFICATIONS
This section describes the operating specifications for the SEH. Cabletron
Systems reserves the right to change these specifications at any time
without notice.
General
Delay Times (Start of Packets):
Twisted Pair to EPIM- A 1.10 µs
Twisted Pair to Twisted Pair 1.00 µs
EPIM-A to Twisted Pair 1.00 µs
Delay Times (JAM):
Twisted Pair to EPIM-A 960 ns
Preamble:
Input: Minimum of 40 bits required
Output: 64 bits min. (last 2 bits are 1, 1)
JAM Output:
Collisions are propagated through
the network using the JAM signal
of an alternating pattern of 1’s and
0’s in accordance with 802.3
specifications for a repeater unit.
Fragment Extension:
Packet fragments are extended to a
minimum of 96 bits using the JAM
[1, 0].
SEH Book Page 5 Tuesday, March 19, 1996 4:12 PM

CHAPTER 2: INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-6 SEH USER’S GUIDE
Fault Protection:
Each segment disconnects itself
from the other segments if 32
consecutive collisions occur, or if
the collision detector of a segment
ison forlonger thanapproximately
110 µs. This fault protection resets
automatically after one packet is
transmitted or received onto the
fault protected segment without
causing a collision.
Power Requirements
The SEH uses a universal power supply. The input power requirements
are listed below.
The power supply has two outputs of +5Vdc and +12Vdc. The maximum
output power is 20 W and the minimum efficiency is 65% under all
conditions of line at full load.
Environmental Requirements
Operating Temperature: +5°to +50°C (41°to 122°F)
Non-operating Temperature: -30°to +90°C (-22°to 194°F)
Operating Humidity: 5% to 95% (non-condensing)
Table 2-1. Power Requirements
Model Voltage Range Frequency
Range
SEH-22/SEH-24 100-125 VAC or
200-240 VAC 50-60 Hz
SEH Book Page 6 Tuesday, March 19, 1996 4:12 PM

OPERATING SPECIFICATIONS
SEH USER’S GUIDE 2-7
Safety
This unit meets the safety requirements of UL1950 (without D3
deviations), CSA C22.2 No. 950, and EN60950.
EMI
This unit meets the EMI requirements of FCC Part 15 ClassA, EN55022
Class A and VCCI Class I.
EMC
This unit meets the EMC requirements of EN 50082-1 including: IEC
801-2 (ESD) levels 1 through 4, IEC 801-3 (Radiated Susceptibility)
levels 1 through 4, and IEC 801-4 (EFT/B) levels 1 through 4.
Physical
Dimensions (H x W x D): 2.8" x 17.0" x 8.5"
(7.2 cm x 43.6 cm x 21.6 cm)
Weight: 4.9 lb (2.22 Kg)
Predicted MTBF: SEH-22/24: 847,921 hours
It is the responsibility of the person who sells the system to
which the SEH will be a part to ensure that the total system
meets allowed limits of conducted and radiated emissions.
WARNING
SEH Book Page 7 Tuesday, March 19, 1996 4:12 PM