Cabletron Systems MR-9T User manual

CABLETRON SYSTEMS, P. O. Box 5005, Rochester, NH 03866-5005
MR9T IEEE 802.3 10BASE-T
MR9T-C IEEE 802.3 10BASE-T/10BASE-2
MULTIPORT REPEATER
INSTALLATION 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 June 1992 by
Cabletron Systems, Inc.
P.O. Box 5005, Rochester, NH 03867-0505
All Rights Reserved
Printed in the United States of America
Order number: 9030521-01 June 1992
LANVIEW is a registered trademark and MMAC,MR9T-C, and
MR9T are trademarks of Cabletron Systems, Inc.
Ethernet is a trademark of Xerox Corp.
Velcro is a registered trademark of Velcro Industries, B.V.
NOTICE

ii
FCC NOTICE
WARNING: This equipment has been tested and found to comply
with the limits for a Class A digital device, pursuant to Part 15
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 at his own expense to correct the
interference.
If this equipment does cause interference to radio or television,
which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of
the following measures:
• Re-orient the receiving antenna.
• Relocate the repeater with respect to the computer.
• Move the repeater away from the receiver.
• Plug the repeater into a different outlet so that the computer
and the repeater are on different branch circuits.
If necessary, you should consult the dealer or an experienced radio/
television technician for additional suggestions. You may find the
following Federal Communication Commission booklet helpful:
“Interference Handbook”
This booklet is available from the U.S. Government Printing Office,
Washington D.C. 20402 - Stock No. 004-000-00482-5.
FCC NOTICE

iii
CONTENTS
CONTENTS
CHAPTER 1 INTRODUCTION
1.1 Using This Manual ....................................................................1-1
1.2 Getting Help...............................................................................1-2
1.3 Overview.....................................................................................1-2
CHAPTER 2 SPECIFICATIONS AND REQUIREMENTS
2.1 Specifications..............................................................................2-1
General Specifications ...............................................................2-1
Twisted Pair Connectors ...........................................................2-2
BNC Interface (Port 9, MR9T-C) ..............................................2-3
Power Supply .............................................................................2-4
Environmental ...........................................................................2-4
Safety ........................................................................................2-4
Physical ......................................................................................2-4
2.2 10BASE-T Network Design Guidelines: MR9T........................2-5
2.3 10BASE-2 Network Design Guidelines: MR9T-C ....................2-6
CHAPTER 3 INSTALLATION
3.1 Mounting the MR9.....................................................................3-1
3.2 Connecting the MR9 to the Power Source ................................3-2
3.3 Strain Relief for the Power Cord...............................................3-2
3.4 Connecting Cables .....................................................................3-3
3.4.1 Cross-Over and Straight-Through ...............................3-3
3.5 Connecting the Network Segment ............................................3-4
3.6 Connecting Twisted Pair Segments to RJ-45 Ports .................3-6
CHAPTER 4 USING LANVIEW
4.1 The LANVIEW Indicators .........................................................4-1

Page 1-1
INTRODUCTION
CHAPTER 1
INTRODUCTION
The MR9T-C 10BASE-T/10BASE-2 Multiport Twisted Pair Repeater
(Figure 1-1) and the MR9T 10BASE-T Multiport Twisted Pair
Repeater (Figure 1-2) conform to all applicable IEEE 802.3
specifications. Each repeater has nine ports. Ports 1 through 8 on
both models are 10BASE-T compliant RJ-45 ports. Port 9 is where
the two repeater models differ. Port 9 on the MR9T has an RJ-45
connector. In addition, the MR9T has a special switch that alters the
pin configuration of Port 9. On the MR9T-C, Port 9 is a BNC
connector for a thin-coax connection. The MR9T-C also has a switch-
selectable internal 50 ohm terminator.
1.1 USING THIS MANUAL
Unless otherwise noted, this manual refers to both the MR9T and
MR9T-C as the MR9.
Chapter 1, Introduction, describes the differences between the
MR9T and the MR9T-C and explains the product features.
Chapter 2, Specifications and Requirements, contains operating
specifications for the MR9. This chapter also includes the location
requirements for the MR9 and network design guidelines for
connecting the MR9 to the network.
Chapter 3, Installation, contains instructions for installing the
MR9 and connecting it to your network.
Chapter 4, Using LANVIEW, contains a functional description of
the LANVIEWindicators.
This manual assumes that you have a general working knowledge of
Ethernet or IEEE 802.3 type data communications networks and
their physical layer components.

Page 1-2
INTRODUCTION
1.2 GETTING HELP
If you need additional support related to the MR9, or if you have any
questions, comments, or suggestions related to this manual, contact
Cabletron Systems Technical Support. Before calling, please have
the following information ready:
• The product type (MR9T or MR9T-C) and the product serial
number. The serial number is located on the front panel of
the repeater.
You can contact Cabletron Systems Technical Support by any of the
following methods:
By phone: Monday through Friday between 8
A.M. and 8 P.M. Eastern Standard
Time at [phone].
By Compuserve: GO CTRON from any !
By Internet mail: [email protected]
1.3 OVERVIEW
The MR9T and MR9T-C have eight internally crossed-over RJ-45
ports. The MR9T has a ninth RJ-45 port which is switch-selectable
for a cross-over or a straight-through pin configuration. (For an
explanation of cross-over and straight-through, see Chapter 3,
Installation.) The configuration switch gives you complete flexibility
to connect to other twisted pair Ethernet devices without using
specially configured cable segments. All RJ-45 ports incorporate a
polarity detection and correction feature which lets the repeater pass
data regardless of the polarity of a port’s twisted pair receive link.
On the MR9T-C, Port 9 has a thin-net coaxial male BNC connector
instead of an RJ-45 connector. Instead of a configuration switch, the
MR9T-C has a termination switch that lets you activate an internal
50 ohm cable terminator for Port 9.
You can use any port to connect the MR9T directly to an Ethernet
network, though Port 9 is normally used for the network connection.
Typically, the MR9T connects to a network hub, such as Cabletron
Systems’ MMAC series. The MR9T-C can connect to a network hub,
or directly to an Ethernet coax cable through a transceiver.

Page 1-3
INTRODUCTION
TERM
MR9T-C
802.3 10BASE-T/10BASE2
MULTI PORT REPEATER
WITH LANVIEW
POWER INPUT
The Complete Networking Solution
PORT9 8X7X6X5X 4X3X2X1X
SN
LISTED
UL
16EO
ITE REPEATER UNIT
TUV Rheinland
THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES.
OPERATION IS SUBJECT TO THE FOLLOWING TWO CONDITIONS:
(1) THIS DEVICE MAY NOT CAUSE INTERFERENCE, AND
(2) THIS DEVICE MUSTACCEPTANY INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.
POWER REQUIRED: 15V - - - , 900mA MAX
DATA CAPABILITY: 10Mb/s
RCV
LNK
PORT 987654321
PWR
CLN
MR9T
802.3 10BASE-T
MULTI PORT REPEATER
WITH LANVIEW
POWER INPUT
The Complete Networking Solution
PORT9 8X7X6X5X 4X3X2X1X
SN
LISTED
UL
16EO
ITE REPEATER UNIT
TUV Rheinland
THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES.
OPERATION IS SUBJECT TO THE FOLLOWING TWO CONDITIONS:
(1) THIS DEVICE MAY NOT CAUSE INTERFERENCE, AND
(2) THIS DEVICE MUSTACCEPTANY INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.
POWER REQUIRED: 15V - - - , 900mA MAX
DATA CAPABILITY: 10Mb/s
RCV
LNK
PORT 987654321
PWR
CLN
=
X
Figure 1-2. The MR9T
Figure 1-1. The MR9T-C

Page 1-4
INTRODUCTION
The MR9 functions include the following:
• Transmit re-timed data packets
• Regenerate the preamble
• Extend collision fragments
• Automatically partition problem segments
• Reconnect non-problem segments
The auto-segment/auto-reconnect feature ensures that if a problem
develops on a segment connected to the MR9, just those devices on
that segment are affected. When the problem is solved, those users
are automatically reconnected to the network.
The MR9 also incorporates Cabletron Systems’ LANVIEW Status
Monitoring and Diagnostic System. Should a problem arise, power
failures, collisions, cable faults or many other problems can be
diagnosed rapidly by scanning the LANVIEW indicators.

Page 2-1
SPECIFICATIONS/REQUIREMENTS
CHAPTER 2
SPECIFICATIONS AND REQUIREMENTS
2.1 SPECIFICATIONS
Listed below are the electrical and physical specifications of the
MR9. Cabletron Systems reserves the right to change these
specifications at any time without notice.
General Specifications
Delay times (any segment in to all segments out)
Start of packet: 700 ns
Collision to JAM: 700 ns
Preamble
Input: 40 bits minimum to 64 bits maximum.
Output: 64 bits minimum (last 2 bits are 1,1).
JAM output: JAM pattern (1,0) is sent to all
segments when one segment detects a
collision.
Minimum packet
repeated: 96 bits including preamble. Packet
fragments are extended using the
JAM data pattern (1,0).
FAULT protection: Segment disconnect occurs after 32
consecutive collisions, or when a
segment’s collision detector is on for
longer than 2 to 3 ms. FAULT
protection resets after one packet is
transmitted onto the FAULTed
segment without causing a collision.

Page 2-2
SPECIFICATIONS/REQUIREMENTS
Twisted Pair Connectors
Type: RJ-45 port, for use with twisted pair
cable. See Figure 2-1.
RJ-45 Port Pin
Configuration: Figure 2-1 shows the MR9T Port 9
straight-through pin configuration, as
indicated by ‘=’ on the switch label.
Figure 2-2 shows cross-over RJ-45
Port pin configuration, ‘X’ on the
switch label. Port 9 of the MR9T is
selectable for cross-over or straight-
through configuration. Ports 1
through 8 on both the MR9T and
MR9T-C use the cross-over
configuration.
Pin 1 TX+
Pin 2 TX-
Pin 3 RX+
Pin 4 No Connection
Pin 5 No Connection
Pin 6 RX-
Pin 7 No Connection
Pin 8 No Connection
MR9T Port 9 123456 87
Figure 2-1. MR9T Port 9 Switched for
Straight-Through Pin Configuration