Cabletron Systems MR-9T, MR9T-C Installation Manual

MR9T IEEE 802.3 10BASE-T

MR9T-C IEEE 802.3 10BASE-T/10BASE-2

MULTIPORT REPEATER

INSTALLATION GUIDE

CABLETRON SYSTEMS, P. O. Box 5005, Rochester, NH 03866-5005

NOTICE

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.

i

FCC NOTICE

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.

ii

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

iii

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 switch­selectable 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 1-1

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: [e-mail]

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 1-2

INTRODUCTION

MR9T-C

802.3 10BASE-T/10BASE2

POWER INPUT

MULTI PORT REPEATER

WITH

LANVIEW

TERM

The Complete Networking Solution

PORT 9 8X7X6X5X 4X3X2X1X

PWR

CLN

RCV
LNK

PORT 987654321

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 MUST ACCEPT ANY INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.

POWER REQUIRED: 15V - - - , 900mA MAX
DATA CAPABILITY: 10Mb/s

LISTED

U

TUV Rheinland

SN

L

16EO

ITE REPEATER UNIT

Figure 1-1. The MR9T-C

PWR

MR9T

802.3 10BASE-T

POWER INPUT

MULTI PORT REPEATER

WITH

LANVIEW

=

The Complete Networking Solution

CLN

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 MUST ACCEPT ANY INTERFERENCE RECEIVED,
INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.

POWER REQUIRED: 15V - - - , 900mA MAX
DATA CAPABILITY: 10Mb/s

SN

X

PORT 9 8X7X6X5X 4X3X2X1X

RCV
LNK

PORT 987654321

LISTED

ITE REPEATER UNIT

U

16EO

TUV Rheinland

L

Figure 1-2. The MR9T

Page 1-3

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 1-4

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 2-1

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.

MR9T Port 9

Pin 1 TX+
Pin 2 TX-

123456 87

Figure 2-1. MR9T Port 9 Switched for

Straight-Through Pin Configuration

Pin 3 RX+
Pin 4 No Connection
Pin 5 No Connection
Pin 6 RX­Pin 7 No Connection
Pin 8 No Connection

Page 2-2

Port 9 Switched

for Crossed-Over

Operation (X)

SPECIFICATIONS/REQUIREMENTS

123456 87

Pin 1 RX+
Pin 2 RX­Pin 3 TX+
Pin 4 No Connection
Pin 5 No Connection
Pin 6 TX­Pin 7 No Connection
Pin 8 No Connection

Figure 2-2. RJ-45 Port Cross-Over Pin Configuration

BNC Interface (Port 9, MR9T-C)

Type: BNC receptacle, with gold center

contact, for use with BNC type plugs
and RG-58 thin-net cable.

Terminations: Internally connected to a switch-

Grounding: The BNC connector shield is not

selectable 50 ohm terminator.

grounded.

Page 2-3

SPECIFICATIONS/REQUIREMENTS
Power Supply

Input Power USA: 90 - 135 Vac, 50-60 Hz at 19.0 W
Input Power UK: 216 - 264 Vac, 50 Hz at 13 W
Input Power Europe: 180 - 240 Vac, 50 Hz at 13 W
Output Power: 0.9 amp at 15 Vdc
Operating Temperature

Range: 0° to 70°C

Note: The power source for the MR9 is to be certified for use in the
country of installation with a SELV output of 15V DC and capable of
providing a minimum of 900mA. The output connector is to be
compatible with TOTAL POWER or MORFOR RJ-01-E connectors.

Environment

Operating Temperature: +5° to +40°C
Heat Output: 64.9 Btu/Hr
Storage Temperature: -30° to +90°C
Operating Humidity: 5 to 95% (non-condensing)

Safety

Designed in accordance with UL478, UL910, NEC 725-2(b), CSA,
IEC, TUV, VDE Class A. Meets FCC part 15 Class A limits.

Warning: It is the responsibility of the person who sells the system to
which the MR9 will be a part to ensure that the total system meets
allowed limits of conducted and radiated emissions.

Physical

Dimensions: 10.16 x 17.78 x 2.28 cm (4 x 7 x .9 in)
Weight

MR9: 363 gm (0.8 lb)
15 Vdc adapter: 409 gm (0.9 lb)

Page 2-4

SPECIFICATIONS/REQUIREMENTS

2.2 10BASE-T NETWORK DESIGN GUIDELINES: MR9T

Transceivers and network devices that connect to the MR9T must
meet IEEE 802.3 standards. Your network must meet the following
IEEE 802.3 10BASE-T Twisted Pair requirements when connecting
devices with the MR9T.

• Segment Length - The IEEE 802.3 10BASE-T standard
requires that 10BASE-T devices support a 100 meter (328
feet) minimum link length using 22-26 AWG unshielded
twisted pair wire. As a general rule, if your link meets the
allowed limits for insertion loss and impedance, links up to
125 meters (410 feet) are possible. Higher quality low
attenuation cables may be required for links greater than
125 meters. Due to cable delay, the maximum link length is
always limited 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 5.0 and
10 MHz. This includes the attenuation of the cables,
connectors, patch panels, and reflection losses due to
impedance mismatches in the cable segment.

• Impedance - Typical unshielded twisted pair cable
impedance is 85 to 110 ohms. Shielded twisted pair cables,
such as Type 1 cable, can also be used. Type 1 cable
impedance is typically 150 ohms. This increases the signal
reflection caused by the cable. Since the cable is shielded,
signal reflection has little effect on the received signal’s
quality due to the lack of crosstalk. Cabletron System’s
10BASE-T Twisted Pair products will work on shielded
twisted pair cable with 75 to 165 ohms of impedance.

• Jitter - Intersymbol interference and reflections can cause
jitter in the bit cell timing, which results in data errors. A
10BASE-T link segment must not generate more than 5.0 ns
of jitter. If your 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.

Page 2-5

SPECIFICATIONS/REQUIREMENTS

• Noise - Noise is caused by either crosstalk (signal coupling
between the different cable pairs in a multi-pair cable, or
externally induced impulses. External noise can cause data
errors if impulses occur at very specific times during data
transmission. Generally you do not have to be concerned
about noise. If you suspect noise related problems, reroute
the cable or eliminate the source of the impulse noise.

• Temperature - Most multi-pair PVC 24 AWG telephone
cables typically have an attenuation of approximately 8 to
100 dB/100 m at 20°C (68°F). The attenuation of PVC
insulated cable varies significantly with temperature. At
temperatures greater than 40°C (104°F), we strongly
recommend that you use plenum rated cables to ensure that
cable attenuation remains within specification.

2.3 10BASE-2 NETWORK DESIGN GUIDELINES: MR9T-C

This section describes guidelines for transceivers and network
devices that connect to Port 9 of the MR9T-C. These devices must
meet IEEE 802.3 10BASE-2 standards. Ports 1 through 8 must meet
10BASE-T guidelines, as described in the previous section.

• Segment Length - The IEEE 802.3 10BASE-2 standard
requires that thin-net link length be no greater than 185
meters (607 feet). A thin coax cable can have a maximum of
30 taps. Taps must be at least 0.5 meters apart.

• Termination - Terminate both ends of a cable segment with
a 50 ohm terminator. The MR9T-C has an internal, switch­selectable, 50 ohm terminator. When enabled, the internal
terminator eliminates the need for connecting the repeater to
the cable with a tee connector and external 50 ohm
terminator.

• Grounding - The BNC port is NOT connected to earth
ground.

Warning: For safety, all thin coax cable segments must have a single
earth ground. Cable segments that are grounded at more than one
point on the segment can develop dangerous ground currents.

Page 2-6

INSTALLATION

CHAPTER 3

INSTALLATION

When you unpack the MR9, verify that you have received the
following:

• One 15 Vdc, 0.9 Amp wall mount transformer with attached

power cord

• Two sets of Velcro mounts

• Ten 6 inch tie wraps

• Four cable clamps

After you are sure that you have met all requirements listed in
Chapter 2, Specifications and Requirements, complete the
installation instructions provided in this chapter.

3.1 MOUNTING THE MR9

Using the two sets of Velcro mounts included in the accessory
package, you can wall mount the MR9.

1. Separate the two Velcro mounts.

2. Peel off the paper that covers the adhesive backing of one Velcro
mount.

3. Carefully position the Velcro on the back of the MR9. Press
firmly so that the adhesive firmly affixes to the unit.

4. Place the other half of Velcro on the surface where you want to
mount the MR9.

5. Mount the repeater by attaching the Velcro-backed MR9 to the
Velcro mount.

Page 3-1

INSTALLATION

3.2 CONNECTING THE MR9 TO THE POWER SOURCE

To connect the repeater to the power source:

1. Plug the power cord (Figure 3-1) into the power receptacle
located on the side of the MR9.

2. Plug the power cord into a wall receptacle.

After you have made the power connection, verify that the PWR LED
is lit, indicating that the repeater is receiving power.

3.3 STRAIN RELIEF FOR THE POWER CORD

To eliminate the possibility of accidently disconnecting the MR9
power cord from the repeater, use one of the cable tie wraps to
anchor the power cord to the MR9 case. Figure 3-1 shows you how
strap the power cord to the tie down loop.

Power Cord

Tie Down Loop

Figure 3-1. Tying Down the Power Cord

MR9T

802.3 10BASE-T

POWER INPUT

MULTI PORT REPEATER

WITH

LANVIEW

=

The Complete Networking Solution

X

PORT 9 8X 7X

Page 3-2

INSTALLATION

3.4 CONNECTING CABLES

In a typical application, the MR9 connects up to eight Ethernet
devices to the Ethernet network. One port connects the repeater to
the network while the other ports connect to Ethernet devices such
as PC network interface cards. Usually, Port 9 is used as the
connection to the network. In operation, Port 9 is the same as any
other port; you can use any port for the network connection.

Port 9 does have features which make it unique. On the MR9T-C,
where Port 9 is a BNC connector, you can select the internal 50 ohm
terminator and eliminate the need for connecting the cable with a tee
connector and external terminator. On the MR9T, where Port 9 is an
RJ-45 connector, you can select between a straight-through or a
cross-over pin configuration.

3.4.1 Cross-Over and Straight-Through

Twisted pair wires have two sets of polarized signals: TX+ and TX-,
and RX+ and RX-. When you connect any two 10BASE-T devices, you
must make sure that the RX pair of one device connects to the TX
pair of the other device as shown in Figure 3-2.

MR9T

Repeater

RX+
RX-

TX+
TX-

10BASE-T

Transceiver

RX+
RX-

TX+
TX-

Figure 3-2. 10BASE-T Signal Pairs

When you connect a transceiver to a repeater, or a transceiver to a
network hub, the pin configurations of the mated RJ-45 connector
and port must maintain the correct signal pair connections. Since a
repeater needs to be able to connect to both a hub (network) and a
transceiver, Port 9 on the MR9T has a configuration switch that lets
you change the port’s pin configuration. When the configuration
switch is set to the straight-through position (=), Port 9 can connect
to the network hub or to another repeater. When set to the cross-over
position, Port 9 can connect to an Ethernet device such as a

Page 3-3

INSTALLATION

transceiver or PC network interface card. Figure 3-3 shows a
representation of a typical twisted pair repeater installation. Pins 1,
2, 3, and 6 in an RJ-45 connector are the pins used to carry the
signals. Repeater Port 1X connects to a transceiver, which connects
to a PC network interface card. The Repeater Port 9 configuration
select switch is set to straight-through (=). Port 9 connects to a
Media Interface Module (MIM) which resides in a network hub and
provides access to the rest of the Ethernet network.

To Ethernet

Network

MR9T

Twisted

Pair MIM

1

RX+

2

RX-

3

TX+

6

TX-

Port 9=

123

TX+ TX- RX+ RX-

6

Twisted

Pair

Transceiver

1

TX+

2

TX-

3

RX+

6

RX-

Port 1X

123

RX+ RX- TX+ TX-

To PC

Network

Interface

Card

6

Figure 3-3. A Typical Repeater Installation

3.5 CONNECTING THE NETWORK SEGMENT

MR9T Port 9 is an RJ-45 port. The MR9T-C has a BNC connector at
Port 9. You can use any port to connect the repeater to the network.

1. If you use an RJ-45 port to connect to the network, connect one
end of a twisted pair segment to a 10BASE-T network hub.

Page 3-4

INSTALLATION

Connect the other end of the twisted pair segment to any port on
the front of the MR9T.

If you are using MR9T Port 9, make sure that the configuration
switch on the side of the MR9T is set correctly, either cross-over
(X) or straight-through (=). If you are unsure of the proper
setting for your application, check the pin configurations of the
RJ-45 ports at each device to be connected. Make sure that you
are connecting TX+ to RX+, TX- to RX-, RX+ to TX+, and RX- to
TX-. Normally, for a connection between the repeater and a
network hub, you would use the straight-through configuration.

If you are using any of Ports 1 through 8 for your network
connection, you must use a twisted pair segment that internally
swaps the signal pairs to maintain the TX to RX configuration

2. To connect an MR9T-C via the BNC connector, connect one end

of a thin coax segment to the repeater and the other end of the
cable to a 10BASE-2 network hub. Both ends of the cable must
be terminated with a 50 ohm terminator. On the MR9T-C you
can select the internal 50 ohm terminator by setting the TERM
switch to the ON “ ” position. Or you can turn the internal
terminator OFF “ ” and connect the coax cable with a tee
connector and external 50 ohm terminator.

Caution: If you use an external terminator, be sure that the
repeater’s internal terminator is turned off. Double termination can
cause unstable network operation.

3. Check that the LNK LED for the connected port is lit. If the LED

is not lit, perform each of the following steps:

a. Check that both the repeater and the network device at

the other end of the cable segment are turned on.

b. Disconnect the cable segment that connects the repeater

to the network hub.

c. For an RJ-45 connection, check the RJ-45 connectors for

proper configuration. The MR9 configuration is listed in
Chapter 2. If you are using MR9T Port 9, check the cross­over switch to ensure that it is in the proper position.

d. Check the cable for continuity.

Page 3-5

INSTALLATION

e. Reconnect the cable segment to the repeater and the

network device.

If a link has not been established, contact Cabletron Systems
Technical Support.

3.6 CONNECTING TWISTED PAIR SEGMENTS TO

RJ-45 PORTS

To connect a workstation or other device to the MR9:

1. Use a twisted pair segment with RJ-45 connectors at each end.
Connect one end of the cable to any RJ-45 port on the MR9.
Connect the other end of the segment to a 10BASE-T device.

Note: If the polarity of the twisted pair segment is reversed, the MR9
senses the mismatch and automatically reconfigures internal
operation to allow the repeater to operate. This automatic detection
and correction feature is a standard feature of Cabletron Systems’
10BASE-T products.

2. Verify that the LNK LED for the applicable repeater port is lit. If
the LED is not lit, perform each of the following steps:

a. Check that the 10BASE-T device at the other end of the

twisted pair segment is turned on.
b. Disconnect the RJ-45 connector from the repeater.
c. Check the pin configuration of the segment RJ-45

connector.

Note: If using port 9, check the configuration switch to ensure that it
is in the proper position for the connector you are using. For normal
installations, select the cross-over (X) configuration.

d. Check the segment for continuity.
e. Reconnect the RJ-45 jack to the RJ-45 port of the MR9.

If a link has not been established, contact Cabletron Systems
Technical Support.

Page 3-6

USING LANVIEW

CHAPTER 4

USING LANVIEW

The MR9 uses Cabletron Systems’ built-in diagnostic and status
monitoring system, LANVIEW. The LANVIEW indicators give you a
visual indication of network status and problems.

This chapter explains how to use the LANVIEW indicators to
monitor network activity and help troubleshoot network problems on
the physical layer.

4.1 THE LANVIEW INDICATORS

The following explains the purpose of each LANVIEW LED on the
MR9. See Figure 4-1.

Power (PWR) LED

When lit, this green LED indicates that the MR9 is receiving power.
If this LED is not lit, the problem may be with the input power, or
with the MR9.

Collision (CLN) LED

This red LED flashes to indicate that a collision is occurring on one
or more segments. The flash of the LED is pulse stretched for
viewing effect. Collision frequency increases as network traffic
increases. If the CLN LED is lit for extended periods, it can indicate
that traffic levels are saturating your network and network
performance is declining.

Note: There are separate LNK and RECEIVE LEDs for each twisted
pair port on the MR9.

Page 4-1

USING LANVIEW
Receive (RVC) LED

This yellow indicator normally flashes to indicate that the MR9 is
repeating data packets received from that segment. The flash of the
LED is pulse stretched for viewing effect.

MR9T

802.3 10BASE-T
MULTIPORT REPEATER

WITH

LANVIEW



PWR

CLN

RCV

LNK

PORT 9 8 7 6 5 4 3 2 1

Figure 4-1. LANVIEW LEDs

Link (LNK) LED

When this green LED is lit, it indicates that a twisted pair link has
been established between the applicable repeater port and the device
at the other end of the segment. Port 9 on the MR9T-C does not have
a LNK LED since Port 9 is a coax connection. The LNK LED remains
lit as long as a link is maintained.

On the MR9T, the Port 9 LNK LED flashes to indicate that the
polarity detection and correction feature has detected a polarity
mismatch on the Port 9 twisted pair RX (Receive) pair. The repeater
will continue to function normally in this condition. Polarity
detection and correction is incorporated into Ports 1 though 8 in
addition to Port 9 but the Port 9 LNK LED is the only one that can
indicate a polarity mismatch.

Page 4-2