Cabletron Systems MRXI-22 User manual

MRXI-22 AND MRXI-24
10BASE-T HUB
USER’S GUIDE
CABLETRON SYSTEMS, P. O. Box 5005, Rochester, NH 03867-5005
The Complete Networking Solution™

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 FORANY 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 May 1993 by:
Cabletron Systems Inc.
P.O. Box 5005, Rochester, NH 03867-5005
All Rights Reserved
Printed in the United States of America
Order Number: 9030637-01 May 93
Remote LANVIEW , LANVIEW , and SPECTRUM are registered trademarks of Cabletron
Systems, Inc.
MRXI and MMAC are trademarks of Cabletron Systems, Inc.
IBM is a registered trademark of International Business Machines Corporation.
CompuServe is a registered trademark of CompuServe.
DEC , VT200 , and VT300 are trademarks of Digital Equipment Corporation.
Ethernet is a trademark of Xerox Corporation.
Hayes is a trademark of Hayes Microcomputer Products Inc.
Windows is a registered trademark of Microsoft Corporation

NOTICE
ii
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 : 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 ClassA 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.

iii
CONTENTS
CHAPTER 1 INTRODUCTION
1.1 USING THIS MANUAL................................................................1-1
1.2 GETTING HELP..........................................................................1-2
1.3 THE 10BASE-T MRXI .................................................................1-2
1.4 LANVIEW LEDs AND LCD DISPLAY..........................................1-4
1.5 LOCAL MANAGEMENT..............................................................1-4
1.6 NETWORK MANAGEMENT CAPABILITIES..............................1-4
1.7 RELATED MANUALS..................................................................1-5
CHAPTER 2 INSTALLATION
REQUIREMENTS/SPECIFICATIONS
2.1 NETWORK REQUIREMENTS....................................................2-1
2.2 SELECTING A LOCATION FOR THE MRXI...............................2-1
2.3 NETWORK GUIDELINES ...........................................................2-2
2.3.1 10BASE-T Twisted Pair Network Requirements ............2-2
2.3.2 Multi Mode Fiber Optic Network Requirements..............2-3
2.3.3 Single Mode Fiber Optic Network Requirements............2-4
2.3.4 Thin-Net Network Requirements ....................................2-5
2.3.5 Transceiver Requirements..............................................2-6
2.3.6 AUI Cable Requirements................................................2-6
2.4 OPERATING SPECIFICATIONS ................................................2-7
CHAPTER 3 INSTALLATION
3.1 UNPACKING THE MRXI.............................................................3-1
3.2 ATTACHING THE STRAIN RELIEF BRACKET..........................3-1
3.3 INSTALLING THE MRXI .............................................................3-2
3.3.1 Rack Mounting the MRXI................................................3-2
3.3.2 Wall Mounting the MRXI.................................................3-3
3.3.3 Free-Standing Installation...............................................3-5
3.4 CONNECTING THE MRXI TO THE POWER SOURCE.............3-6
3.5 CONNECTING THE MRXI TO THE NETWORK.........................3-6
3.5.1 Connecting the Network Port Cabling.............................3-7
3.5.2 Connecting a Twisted Pair Segment to an EPIM-T ........3-8
3.5.3 Connecting an AUI Cable to an EPIM-X.......................3-10
3.5.4 Connecting a Fiber Optic Link Segment to an
EPIM-F1, EPIM-F2, or EPIM-F3...................................3-11
3.5.5 Connecting a Thin-Net Segment to an EPIM-C............3-13
3.5.6 Connecting an AUI Cable to an EPIM-A.......................3-14
3.6 FINISHING THE INSTALLATION..............................................3-15

CONTENTS
iv
CHAPTER 4 TESTING ANDTROUBLESHOOTING
4.1 INSTALLATION CHECK-OUT.....................................................4-1
4.2 TESTING SEGMENTS ATTACHED TO THE MRXI....................4-2
4.3 USING LANVIEW ........................................................................4-5
4.4 THE LCD DISPLAY .....................................................................4-6
CHAPTER 5 LOCAL MANAGEMENT
5.1 TERMINAL CONFIGURATION....................................................5-1
5.1.1 Console Cable Configuration ..........................................5-3
5.1.2 Modem Cable Configuration............................................5-5
5.1.3 Cable Configuration for UPS...........................................5-5
5.2 ACCESSING LOCAL MANAGEMENT ........................................5-6
5.3 COMMUNITY NAME TABLE.......................................................5-7
5.3.1 Accessing the Community Name Table Screen..............5-8
5.3.2 Community Name Table Screen Fields...........................5-8
5.3.3 Editing the Community Name Table Screen...................5-9
5.4 CONFIGURING THE MRXI .......................................................5-10
5.4.1 Accessing the Configuration Screen.............................5-10
5.4.2 Configuration Screen Fields..........................................5-11
5.4.3 Setting the IP Address Table and SubNET Mask Field.5-12
5.4.4 Setting the Default Gateway..........................................5-13
5.4.5 Setting the UPS Option.................................................5-13
5.4.6 Using the Port LOCK Override Option ..........................5-14
5.4.7 Using the Port ENABLE Override..................................5-14
5.5 SETTING THE TRAP TABLE ....................................................5-15
5.5.1 MRXI Trap Table Screen...............................................5-15
5.5.2 Trap Table Screen Fields..............................................5-16
5.5.3 Configuring the Trap Table............................................5-16
5.6 SNMP TOOLS ...........................................................................5-17
5.6.1 Accessing the SNMP Tools Screen ..............................5-18
5.6.2 SNMP Tools Screen Fields...........................................5-18
5.6.3 Using SNMP Tools........................................................5-19
5.7 COMMAND LINE INTERFACE (CLI).........................................5-22

1-1
CHAPTER 1
INTRODUCTION
Welcome to the Cabletron Systems MRXI-22 and MRXI-24 10BASE-T
HUB User’s Guide
. This manual provides installation instructions and
presents reference information for the MRXI-22 and MRXI-24
10BASE-T Hubs.
Note :Throughout this manual the term MRXI is used to cover both the
MRXI-22 and MRXI-24 unless otherwise specified.
1.1 USINGTHIS MANUAL
Read through this manual completely to familiarize yourself with its
content and to gain an understanding of the features and capabilities of
the MRXI. A general working knowledge of Ethernet and IEEE 802.3
type data communications networks and their physical layer components
will be helpful when installing the MRXI.
Chapter 1,
Introduction , outlines the contents of this manual, briefly
describes features of the MRXI, and concludes with a list of related
manuals.
Chapter 2,
Requirements/Specifications , describes installation
requirements, network guidelines, and MRXI operating specifications.
Chapter 3, Installation , contains instructions for installing your MRXI
and connecting it to the network using the various media types.
Chapter 4, Testing and Troubleshooting, contains procedures for testing
the MRXI after installation, a description of the LANVIEW ™ LEDs, and
explains the use of the front panel LCD display.
Chapter 5,
Local Management, describes how to access Local
Management. It also describes each of the Local Management screens and
the available commands.

INTRODUCTION
1-2
1.2 GETTING HELP
If you need additional support related to the MRXI-22 or MRXI-24, or if
you have any questions, comments, or suggestions concerning this
manual, feel free to contact Cabletron Systems Technical Support:
By phone ..........................[phone]
Monday-Friday; 8am - 8pm EST
By CompuServe
®
.............GO CTRON from any ! prompt
By Internet mail ...............[email protected]
1.3 THE 10BASE-T MRXI
The MRXI-22 and MRXI-24 are functionally identical. The MRXI-22
provides twelve RJ-45 connectors and the MRXI-24 provides twenty-four
RJ-45 connectors for network ports. Additional network connections are
made through the use of front panel EPIM modules (one module for the
MRXI-22, two modules for the MRXI-24). A variety of EPIMs are
available permitting the expansion of an Ethernet/802.3 network via:
• Unshielded Twisted Pair Cable from the 10BASE-T Twisted Pair
Interface Module (EPIM-T).
• Fiber Optic Cable, with SMA or ST connectors, from the Fiber Optic
Interface Modules (EPIM-F1, EPIM-F2 or EPIM-F3).
• Thin-Net Cable from the Coaxial Interface Module (EPIM-C).
• AUI Cable from the AUI Interface Module (EPIM-A or
EPIM-X).
Figure 1-1 The MRXI-24
MRXI-24
10BASE-T HUB with LANVIEW
The Complete Networking Solution

INTRODUCTION
1-3
The MRXI fully conforms to the IEEE 802.3 Repeater, AUI, and
10BASE-T specifications, and provides the flexibility to connect
networks using IEEE 802.3, EthernetVersion 1 orVersion 2 equipment.A
Repeater Interface Controller (RIC) in the MRXI provides full 802.3
repeater capabilities integrated into a single chip. The MRXI transmits
re-timed data packets, regenerates the preamble, extends fragments, and
arbitrates collisions.
The MRXI automatically partitions problem segments, and reconnects
non-problem 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 MRXI automatically reconnects
the isolated segment to the network.
Since the MRXI utilizes polarity detection and correction, the twisted pair
connections are not sensitive to signal polarity. The network will still
function properly with the (+) and (–) lines within a pair reversed.
Operating in this condition is not recommended and if this condition is
discovered, the segment should be removed from the network and wired
correctly by a technician. This reduces the potential for problems in the
future if equipment changes are made. Connector pinouts are provided in
Chapter 2,
Installation Requirements / Specifications .
You can configure the two front panel serial ports to support an SNMP
proxy for Uninterruptible Power Supplies (UPS) or the Serial Line
Internet Protocol (SLIP). MIB II and RMON support are built into the
MRXI for network analyzer functionality. In addition, Cabletron’s
Distributed LAN Monitor (DLM), a software option for the MRXI,
provides a method for locally polling and monitoring devices on a LAN to
minimize network management traffic on an enterprise, campus, or wide
area network.
The MRXI uses Flash EEPROMs that allow you to download new and
updated firmware using Cabletron Systems Remote
LANVIEW/Windows, version 2.3 or later or any device using BOOTP or
TFTP protocols.
The front panel of the MRXI also has a reset switch to initialize the
processor.

INTRODUCTION
1-4
1.4 LANVIEW LEDS AND LCD DISPLAY
Cabletron Systems’LANVIEW Status Monitoring and Diagnostics
System is a convenient troubleshooting tool that helps you diagnose
power failures, collisions, cable faults, and link problems.
The front panel LCD display provides information about the MRXI such
as power up diagnostics, revision levels, MAC and IP addresses, and error
alerts.
1.5 LOCAL MANAGEMENT
There are two RJ-45 ports on the front panel of the MRXI that let you
access Local Management by connecting a DEC VT
™
320 terminal or a
PC using VT320 emulation software. Refer to Chapter 5,
Local
Management
.
1.6 NETWORK MANAGEMENT CAPABILITIES
The MRXI can be controlled and managed by any SNMP network
management system. These include:
• Cabletron Systems SPECTRUM
®
• Cabletron Systems Remote LANVIEW
®
/Windows
™
• Cabletron Systems Remote LANVIEW
®
for SunNet
™
Manager
• Third Party SNMP compliant Network Management Packages
The MRXI network management capabilities provide the necessary
management tools for the MRXI to operate at its full capacity.Your ability
to set up parameters with network management ensures optimal
performance of the MRXI.
For example, you can gather a large amount of statistical information
about the MRXI, including the number of:
• Packets • Receive Collisions
• Transmit Collisions • Giant Packets
• Runt Packets • Misaligned Packets
• CRC Errors • Out of Window Collisions
• Bytes Received

INTRODUCTION
1-5
For specific information, refer to the applicable network management
package user’s manual.
1.7 RELATED MANUALS
Use the following manual to supplement the procedures and other
technical data provided in this manual. The procedures contained in the
following manual are referenced where appropriate, but not repeated in
this manual.
Cabletron Systems
LAN-MD Portable Ethernet Tester User's Manual.

INTRODUCTION
1-6

2-1
CHAPTER 2
INSTALLATION
REQUIREMENTS/SPECIFICATIONS
This chapter describes network guidelines, power requirements, and
operating specifications for the MRXI. Be sure that you read this chapter
before you install the MRXI.Your 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 NETWORK REQUIREMENTS
When connecting a network segment to the MRXI, via a transceiver and
an AUI cable, the following network requirements must be met:
• The transceivers used to connect the MRXI meet EthernetVersion 2 or
IEEE 802.3 standards.
• The AUI cables connecting the MRXI to the transceivers on the
network match the transceiver type on the network segment, Ethernet
Version 1, Version 2, or IEEE 802.3 type cables, and do not exceed 50
meters in length.
2.2 SELECTING A LOCATION FORTHE MRXI
You can mount the MRXI on a wall, a 19-inch rack, or place it on any
horizontal surface. If you choose not to install the MRXI in a 19-inch
rack, the location must be within reach of the network cabling and meet
the requirements listed below:
• An unrestricted free surface area at least 21 inches wide, 18 inches
deep, and 6 inches high is needed.
• A single phase 120 Vac, 15A, grounded power receptacle must be
located within 7 feet of the location.
• If you use a shelving unit, it must be able to support 30 pounds of static
weight.
• The temperature for the selected location must be maintained between
5
° and 50 ° C, and fluxuate less than 10 ° C per hour.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-2
2.3 NETWORK GUIDELINES
Take care in planning and preparing the connections and the cables for
your network. The quality of the connections, the length of the cables, and
the location of the MRXI are critical factors in determining the reliability
of your network. The following sections describe the network guidelines
to operate this equipment.
2.3.1 10BASE-TTwisted Pair Network Requirements
The device at the other end of the twisted pair segment must meet IEEE
802.3 10BASE-T specifications. When you connect a 10BASE-T Twisted
Pair Segment to the MRXI’s 10BASE-T Twisted Pair Ports, the following
network requirements must be met:
•
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. As a general rule, links up
to 130 meters in length for unshielded twisted pair and 200 meters in
length for shielded twisted pair are achievable. For each connector or
patch panel in the link, subtract 12 meters from the 150 meter limit.
This allows for links of up to 126 meters using standard 24AWG UTP
wire and two patch panels within the link. Higher quality low
attenuation cables may be required when using links of greater than
126 meters. Due to cable delay, the maximum link length is always
limited 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 - Unshielded twisted pair cables typically have an
impedance of between 85 to 110 ohms. Shielded twisted pair cables,
such as IBMType 1 cable, can also be used.You should remember that
the impedance of IBM Type 1 cable is typically 150 ohms. This
increases the signal reflection caused by the cable, but since 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. Cabletron Systems 10BASE-T Twisted Pair products will work
on twisted pair cable with 75 to 165 ohms impedance.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-3
• Jitter - Intersymbol interference and reflections can cause jitter in the
bit cell timing, resulting in data errors. A 10BASE-T link must not
generate more than 5.0 nsec. of jitter. If your cable meets the
impedance requirements for a 10BASE-T link, jitter should not be a
concern.
•
Delay -The maximumpropagationdelayofa 10BASE-Tlinksegment
must not exceed 1000 nsec.This 1000 nsec. 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 can be 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 telephone cables typically
have an attenuation of approximately 8 to 10 dB/100m at 20
° C (78 °
F). The attenuation of PVC insulated cable varies significantly with
temperature.At temperatures greater than 40
° C (104 ° F), it is strongly
recommended that you use plenum-rated cables to ensure that cable
attenuation remains within specification.
2.3.2 Multi Mode Fiber Optic Network Requirements
When you connect a Fiber Optic Link Segment to the MRXI with a Single Port
Fiber Optic Interface Module (EPIM-F1 or EPIM-F2), the following network
requirements must be met:
• Cable Type - The EPIM-F1 and EPIM-F2 are designed for use with
one of the following multimode fiber optic media:
- 50/125
µ m fiber optic cabling.
- 62.5/125
µ m fiber optic cabling.
- 100/140
µ m fiber optic cabling.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-4
• Attenuation - The fiber optic cable must be tested with a fiber optic
attenuation test set that is adjusted for an 850 nm wavelength.This test
verifies that the signal loss in a cable is within an acceptable level:
- 13.0 dB or less for 50/125 fiber cable segment.
- 16.0 dB or less for 62.5/125 fiber cable segment.
- 19.0 dB or less for 100/140 fiber cable segment.
•
Budget and Propagation Delay - When determining the maximum
fiber optic cable length, the fiber optic budget delay and total network
propagation should be calculated and taken into consideration before
fiber optic cable runs are incorporated in any 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 a packet to travel from the sending device
to the receiving device.
•
Length - The maximum allowable fiber optic cable length is
2 km. However, IEEE 802.3 specifications allow for a maximum of 1
km.
2.3.3 Single Mode Fiber Optic Network Requirements
When you connect a Single Mode Fiber Optic Link Segment to the MRXI
with a Fiber Optic Ethernet Port Interface Module (EPIM-F3), the
following network requirements must be met:
• The fiber optic link segment should consist of 8/125 - 12/125
µ m
single mode
µ m fiber optic cabling.You can also use 62.5/125 µ m
multimode cable, howeveropticallosswill begreaterwith multimode
cable and distances will be limited to 2 km.
• The fiber optic cable must be tested with a fiber optic attenuation test
set that is adjusted for a 1300 nm wave length. This test verifies that
the signal loss in a cable is within an acceptable level of 10.0 dB or less
for any given single mode fiber optic link.
• When determining the maximum fiber optic cable length, the fiber
optic budget (total loss of 10.0 dB or less between stations) and total
networkpropagation delay should be calculated and consideredbefore
fiber runs are incorporated in any network design.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-5
• Fiberopticbudgetis the combination of theopticallossdueto the fiber
opticcable,in-linesplices,and fiber optic connectors (the loss for each
splice and connector is typically 1 dB or less).
• Propagation delay is the amount of time it takes a packet to travel from
the sending device to the receiving device. Total propagation delay
allowed for the entire network is 25.6
µ sec. If the total propagation
delay between any two nodes on the network exceeds 25.6
µ sec, then
bridges should be used.
• When using single mode fiber optic cable, segment lengths up to 10
km are possible if system budgets are met. However, IEEE 802.3
FOIRL specifications allow for a maximum length of 1 km.
2.3.4 Thin-Net Network Requirements
When you connect a Thin-net segment to the MRXI with a Coax Interface
Module (EPIM-C), the following network requirements must be met:
• Cable Type - 50 ohm RG-58A/U type coaxial cable must be used
when making up a thin-net cable segment.
• Length - The thin-net segment must be no longer than 185 meters.
•
Terminations -A 50 ohm terminator must be connected to the far end
of each thin-net segment.
• Connections - A maximum of 29 tee-connectors may be used
throughout the length of cable segment for host connections. If an
excessive number of barrel connectors are used within the cable
segment, such as finished wall plates with BNC feed-throughs, then a
reduced number of host connections may be required. For special
network design, contact Cabletron Systems Technical Support.
•
Grounding - For safety, only one end of a thin-net segment should be
connected to earth ground. Connection to earth ground at more than
one point on the segment could produce dangerous ground currents.
The BNC ports of the Coaxial Interface Modules are not connected to
earth ground.
Warning : Do not connect the shield at both ends of a thin net segment to
ground.Only one end of the shield should be connected to earth ground.
Multiple ground paths can introduce noise or a hazardous voltage
potential onto the cable.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-6
2.3.5 Transceiver Requirements
When you connect an external network segment, via a transceiver, to the
MRXI 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 if you connect it to a repeater or to an EthernetVersion 1.0
device. In addition, some Version 2.0 equipment does not support the
SQE test. Devices that do not support SQE test interpret the SQE test
pulse as a collision.
2.3.6 AUI Cable Requirements
When you connect an external network segment to the MRXI with an
EPIM-A or EPIM-X, the AUI cable must meet the following
requirements:
•
AUI Cable - The AUI cable connecting the module to a device must
be IEEE 802.3 type cable.
• Length - The AUI Cable must not exceed 50 meters in length. If 28
AWG thin office drop AUI cable is used, then the maximum cable
length is limited to 50 feet (15.24 meters).
•Grounding - The connector shell of the EPIM-A and the EPIM-X are
connected to ground.

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-7
2.4 OPERATING SPECIFICATIONS
The operating specifications for the MRXI are described in this section.
Cabletron Systems reserves the right to change these specifications at any
time without notice.
GENERAL
Operating System Memory: 4 MB
Internal Processor: Intel 80C960CA operating at
24 MHz
Ethernet Controller: National Semiconductor
DP83932
Static RAM: 128 KB with battery back-up
EPROM: 128 KB
FLASH MEMORY: 2 MB
Delay Times (Start of Packets):
Twisted Pair to EPIM- A 900 nsec.
Twisted Pair to Twisted Pair 1 msec.
EPIM-A to Twisted Pair 750 nsec.
Delay Times (JAM):
Twisted Pair to EPIM-A 1.16 msec.
Preamble:
Input: Minimum of 40 bits required.
Output: 64 bits min. (last 2 bits are 1, 1).

INSTALLATION REQUIREMENTS/SPECIFICATIONS
2-8
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].
Fault Protection: Each segment will disconnect itself from
the other segments if 31 consecutive
collisions occur, or if the collision detector
of a segment is on for longer than
approximately 110 µs. This fault
protection will reset automatically after
one packet is transmitted/received onto the
fault protected segment without causing a
collision.
INTERFACE CONNECTORS
Network (Twisted Pair) Interface
Type: Internally Crossed Over RJ-45 Connector
Pin-out for RJ-45 Connector
Pin 1 RX+ 5 No Connection
2 RX- 6 TX-
3 TX+ 7 No Connection
4 No Connection 8 No Connection