Lantronix LTR8T User manual

LTR-T Installation Guide

Thank you for choosing the Lantronix LTR-T repeater.
Like all Lantronix products, the LTR-T is designed and built to exacting standards. We
strive to make all of our products easy to use and of the highest quality. That’s how we’re
able to support them with a five-year warranty and free technical support.
I hope you find this manual easy to use and thorough in its explanation of the LTR-T
installation process.
Brad Freeburg
President

The information in this guide is subject to change without notice. The manufacturer
assumes no responsibility for any errors which may appear in this guide.
DELNI, Thinwire, and Thickwire are trademarks of Digital Equipment Corporation.
Copyright © 1993, Lantronix.
All rights reserved. No part of the contents of this guide may be transmitted or
reproduced in any form or by any means without the written permission of Lantronix.
Printed in the United States of America.
The revision date for this manual is 6 May 1996
Part Number: 900-006
Rev. A
WARNING
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 operating in a commercial
environment. This equipment generates, uses, and can radiate radio frequency energy,
and if not installed and used in accordance with this guide, 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, at his or her own expense, will be required to take whatever measures may
be required to correct the interference.
Caution: changes or modifications to this device not explicitly approved by Lantronix
will void the user’s authority to operate this device.
Cet appareil doit se soumettre avec la section 15 des statuts et règlements de FCC. Le
fonctionnement est subjecté aux conditions suivantes:
(1) Cet appareil ne doit pas causer une interférence malfaisante.
(2) Cet appareil doît accepter n’importé quelle interférence reçue qui peut causer
une opération indésirable.

Table Of Contents
Overview ....................................................................................................1
Guide to this Manual ............................................................................................1
Site Preparation and Unpacking .............................................................2
Space Requirements .............................................................................................2
Environmental Considerations .............................................................................2
Installation of Other Hardware Components........................................................ 4
Checking the Cable Connections.......................................................................... 4
Unpacking the Unit...............................................................................................4
Installation .................................................................................................5
Network Configuration.........................................................................................5
Cabling Instructions.............................................................................................. 7
Adding New Network Segments.......................................................................... 9
Power-up Sequence.................................................................................10
Troubleshooting.................................................................................................. 12
Normal Operation ...............................................................................................13
Configuration ..........................................................................................14
Configuration Mode ...........................................................................................15
Storing Configuration .........................................................................................17
Factory Defaults .................................................................................................17
10BASE-T Wiring Conventions.........................................................................18
Hub Interconnection ...........................................................................................19
Maintenance Information ...................................................................................19
Glossary....................................................................................................20
Appendix A - Power Supply Cord.........................................................23
Appendix B - Cabling .............................................................................25
Lantronix Problem Report Procedure.................................................................27
Warranty..................................................................................................29

Figures and Tables
Figures:
Figure 1: LTR-T dimensions ..........................................................................2
Figure 2a: A Simple Network Configuration ...................................................6
Figure 2b: A Complex Network Configuration................................................6
Figure 3: LTR-T front and back panels ..........................................................7
Figure 4: Connecting the transceiver cable to the AUI port...........................8
Figure 5: Hub Interconnect Configuration....................................................19
Tables:
Table 1: LTR-T Power Requirements...........................................................3
Table 2: Parts List..........................................................................................4
Table 3: Power-up Diagnostic codes...........................................................11
Table 4: Port Status LEDs...........................................................................13

LTR-T Installation Guide 1
Overview
The LTR8T and LTR16T are 10BASE-T hub/repeaters that receive Ethernet traffic from
one cable segment and repeat that data to all of the other attached segments. The units
provide 8 (LTR8T) or 16 (LTR16T) RJ-45 connection to 10BASE-T media. The
10BASE-T media is phone-grade (or better) unshielded twisted pair cable, also called
UTP. The hubs also provide one (LTR8T) or two (LTR16T) standard 15-pin AUI
connectors for interfacing to Thickwire media or other media via an external transceiver.
Each 10BASE-T segment can be connected to either a network node or to another
10BASE-T hub for further network distribution.
In the discussions below, the term LTR-T will be used to refer to both the LTR8T and the
LTR16T, which are considered functionally equivalent.
LTR-T Features
The LTR-T has the following features:
• meets IEEE 802.3 repeater specifications.
• 8 or 16 (LTR16T) 10BASE-T ports for direct connection to UTP cable segments
of up to 100 meters each.
• 1 or 2 (LTR16T) AUI ports for attachment of external Thinwire (10BASE2),
Thickwire (10BASE5), or UTP (10BASE-T) transceivers.
• separate status and activity LEDs for each port.
• user-friendly interface allows configuration of link test and polarity correction
and manual partitioning of individual ports.
• automatic port partitioning disables malfunctioning network segments and records
the event to aid in network troubleshooting.
• optional stringent reconnection algorithm for reinstatement of automatically
partitioned ports.
• 1 or 2 (LTR16T) user configurable ports simplify repeater to repeater
connections.
• small physical size.
• easy installation.
Guide to this Manual
The rest of this manual covers unpacking and installation instructions, diagnostics, and
configuration of the LTR-T. Appendix A lists the power supply cord specifications for
use outside the U.S. and Canada. Appendix B explains different kinds of cables you can
use and rules you must follow to set up your network. A glossary is also provided to
explain any unfamiliar terms.

2LTR-T Installation Guide
Site Preparation and Unpacking
Before installing the LTR-T, do the following to prepare your site:
• Check space requirements
• Confirm that the LTR-T will have the proper environmental conditions
• Check the installation of other hardware components
• Check the cable connections
• Unpack the unit, making sure all of the parts are enclosed
Each item in this list is explained in detail in this section.
Space Requirements
The table below shows the dimensions of the LTR-T. Allow two inches of space on each
side of the unit for ventilation.
LTR-8T LTR-16T
Width 8.5” 8.5”
Depth 5.5” 5.5”
Height 2.8” 3.8”
Figure 1: LTR-T Dimensions
Environmental Considerations
The following paragraphs list the power and temperature requirements, altitude
limitations, and relative humidity limitations of the LTR-T. Check these values to
guarantee that the LTR-T can operate in the chosen location.
Power Requirements
Table 1 lists the power requirements for the LTR-T. Note that the unit can operate using
either 110 Vac or 220 Vac outlets. There are no switches or jumpers to change for
international (220 Vac) use. Refer to Appendix A for power supply cord specifications
for use outside the U.S. and Canada.

LTR-T Installation Guide 3
Voltage 95-250 Vac 3-wire single phase, autoranging
Frequency 47 to 63 Hz
Operating current 0.5 Amp (maximum)
Power 30 Watts
Fuse (field replaceable) 2 Amp 250 Vac, time delay
Table 1: LTR-T Power Requirements
Fuse
Under normal use, the fuse should not need to be replaced. If it does, ensure that the
proper type of fuse is used. Never replace the fuse with the unit plugged in.
*** CAUTION: For continued protection against the risk of fire, replace only with the
same type and rating of fuse: T2A/250V.
*** AVIS: Pour la protection continuante contre le risque d’incendie remplacer
seulement par le même type et le cote de fusible: T2A/250V.
*** VORSICHT: Zum Schutz gegen das Risiko eines Brandes darf die Sicherung nur mit
einer mit gleichen technischen Daten ersetzt werden: T2A / 250V.
Temperature Limitations
• Operating: 5°to 50°C (41°to 122°F)
• Nonoperating: -40°to 66°C (-40°to 151°F)
Rapid temperature changes may affect operation. Therefore, do not operate the LTR-T
near heating or cooling devices, large windows, or doors that open to the outside.
Maximum temperature change per hour is 20°C (36°F).
Altitude Limitations
• Operating: 2.4 km (8,000 ft.)
• Nonoperating: 9.1 km (30,000 ft.)
If you are operating the LTR-T above 2.4 km (8,000 ft.), decrease the operating
temperature by 1.8°C for each additional 1,000 m (1°F for each 1,000 ft.).
Relative Humidity Limitations
• Operating: 10% to 90% noncondensing (40% to 60% recommended)
• Nonoperating: 10% to 90% noncondensing

4LTR-T Installation Guide
Installation of Other Hardware Components
Ensure that the 10BASE-T (UTP) cables you will be using have been tested and labeled.
See the cable pinouts in Appendix C, if necessary.
If you will be connecting the LTR-T to a Thinwire segment, you will need an LTX-2 or
equivalent 10BASE2 transceiver to attach the segment to the LTR-T’s AUI port.
If connecting to a Thickwire segment, an LTX-5 or equivalent 10BASE5 transceiver will
be required as well as an AUI cable of the necessary length.
If you will be connecting the LTR-T to a Local Network Interconnect (DELNI or
equivalent) you will need an AUI cable between the DELNI and the LTR-T’s AUI port.
Checking the Cable Connections
Make sure you have enough cable to connect the LTR-T to your network. There are three
types of cable connections you must consider:
• 10BASE-T (UTP) segments: one or more, each up to 100 meters long.
• Power: outlet should be within 1.8 m (6 ft) of the LTR-T.
• AUI cable: up to 50 meters if going directly to a transceiver, or 45 meters total if
using a Local Network Interconnect (LNI) device. Consult your LNI manual to
verify the latter value.
Unpacking the Unit
As you unpack the LTR-T, make sure the parts listed in Table 2 are enclosed. If you have
not received a complete LTR-T unit, contact your dealer immediately.
Description of part Quantity
Multiport Repeater (LTR-T) 1
U. S. power cord 1
This manual 1
Table 2: Parts List

LTR-T Installation Guide 5
Installation
Network Configuration
Figure 2 shows two sample network configurations using the LTR-T. Figure 2a shows a
simple network configuration using only 10BASE-T segments; Figure 2b shows a more
complex configuration using Thickwire Ethernet and interconnected LTR-T units. In
Figure 2b, the LTR-T on the left is directly connected from the AUI to the transceiver,
while the LTR-T on the right is connected from the AUI to a Local Network Interconnect
device.
You can connect one or more 10BASE-T segments to the LTR-T, one to each port on the
back of the unit. Additionally, you can connect multiple LTR-T units together, making
sure that there are no more than four LTR-T units between any two nodes. See the
Interconnection section below for important notes about interconnecting LTR-Ts. You
can also attach a transceiver to the AUI port to attach to 10BASE-T or Thinwire media.
If you need more information about rules you must follow when setting up your network,
refer to Appendix B.

6LTR-T Installation Guide
95-250V~50-60Hz 0.5A T2A/250V
This equipment complies with the requirements in Part 15 of FCC Rules for a Class A Computing
and TV reception requiring the operator to take whatever steps necessary to correct the interference.
device. Operation of this equipment in a residential area may cause unacceptable interference to radio
CAUTION
For continued protection against
risk of fire, replace only with
same type and ratings of fuse
Serial #
®
geprüfte
Sicherheit
AUI 187654321
LTR8T
MDI-X
MDI-X
MDI
HostHost
Workstation
Workstation
Figure 2a: A Simple Network Configuration
95-250V~50-60Hz 0.5
A
T2A/250
V
This equipment complies with the requirements in Part 15 of FCC Rules for a Class A
C
and TV reception requiring the operator to take whatever steps necessary to correct th
device. Operation of this equipment in a residential area may cause unacceptable interfer
e
CAUTION
For continued protection again
s
risk of fire, replace only
w
same type and ratings of f
u
Serial#
®
geprüfte
Sicherheit
AUI187654321
LTR 8
T
MDI-X
MDI-X
MDI
THICKWIRE
ETHERNET LTX-5LTX-5
TRANSCEIVER TRANSCEIVER
Local Network
Interconnect
host
95-250V~50-60Hz 0.5
A
T2A/25
0
This equipment complies with the requirements in Part 15 of FCC Rules for a Class A
C
and TV reception requiring the operator to take whatever steps necessary to correct th
device. Operation of this equipment in a residential area may cause unacceptable interfer
e
CAUTION
For continued protection again
s
risk of fire, replace only
w
same type and ratings of f
u
Serial#
®
geprüfte
Sicherheit
AUI187654321
LTR 8
T
MDI-X
MDI-X
MDI
95-250V~50-60Hz 0.5
A
T2A/25
0
This equipment complies with the requirements in Part 15 of FCC Rules for a Class A
C
and TV reception requiring the operator to take whatever steps necessary to correct th
device. Operation of this equipment in a residential area may cause unacceptable interfer
e
CAUTION
For continued protection again
s
risk of fire, replace only
w
same type and ratings of f
u
Serial#
®
geprüfte
Sicherheit
AUI187654321
LTR 8
T
MDI-X
MDI-X
MDI
Figure 2b: A Complex Network Configuration

LTR-T Installation Guide 7
Cabling Instructions
As you follow these instructions, refer to Figure 3 for an illustration of the LTR-T back
panel. Figure 3 shows the location of the 10BASE-T ports, AUI port, power cord, and
fuse.
Fuse
AC input
95-250V~50-60Hz 0.5
A
T2A/25
0
This equipment complies with the requirements in Part 15 of FCC Rules for a Class A Computing
and TV reception requiring the operator to take whatever steps necessary to correct the interference.
device. Operation of this equipment in a residential area may cause unacceptable interference to radio
CAUTION
For continued protection again
s
risk of fire, replace only wi
t
same type and ratings of fu
s
Fabriqué aux Etats-Uni
s
Made in U.S.A.
Serial UL
®
UL 1950
LISTED - 6J40
Equipment
®
LR 89493 IEC 950
geprüfte
Sicherheit
AUI
1
87654321
LTR 8T
MDI-
X
MDI-
X
MDI
15 pin AUI por
t
10BASE-T ports
AUI and 10BaseT Status
Figure 3: LTR-T Back and Front Panels
01
PW
R
CO
L
STA
T
AC
T
AUI 1 2 3 4 5 6 7 8
---MODE---
LTR8T
Figure 3: LTR-T Front and Back Panels
WARNING:
During the installation procedure some segments of your
network may be unstable. Individual packets on the attached
segments may be lost when new segments are added.
1. Label the 10BASE-T cables. Make sure each end of every cable is marked with
its LTR-T port number and destination. It is important that cable routing and all
connections to the UTP cables are documented. This information is valuable
during troubleshooting, maintenance, or reconfiguration of your network.

8LTR-T Installation Guide
2. Connect each 10BASE-T cable to the LTR-T. Make sure the port number on
the LTR-T matches the label on the cable, then insert one end of the cable into the
connector. Connect the other end of the cable to the workstation, host, or network
device. The AUI port and unused UTP ports can be left unconnected if not
needed.
3. AUI attachments: If you wish to use the AUI port as either a connection to a
backbone or as another 10BASE-T port, you will need to attach a transceiver to
the AUI port. Note that an AUI cable may be necessary between the LTR-T’s
AUI port and the transceiver itself. The AUI port can be connected to Thickwire,
Thinwire, or UTP by simply using an LTX-5, LTX-2 or LTX-T, respectively.
To connect the transceiver or AUI cable to the LTR-T, first unlock the slide latch
on the connector by sliding the clip to the right. You may have to slightly loosen
the screws on either side of the connector to move the latch. Next, connect the
transceiver or cable connector to the AUI port of the LTR-T (Figure 4). Finally,
lock the transceiver cable in place by sliding the latch to the left.
95-250V~50-60Hz
0.5A T2A/25
0
This equipment complies with the requirements in Part 15 of FCC Rules for a Cla
s
and TV reception requiring the operator to take whatever steps necessary to correc
t
device. Operation of this equipment in a residential area may cause unacceptable int
e
CAUTION
For continued protection agai
n
risk of fire, replace only wi
same type and ratings of f
u
Serial #
®
geprˇÔte
Sicherheit
AUI 1
87654321
LTR 8
T
MDI-X
MDI-X
MDI
Figure 4: Connecting the AUI cable to the AUI port
UNLOCK
AUI
Figure 4: Connecting the Transceiver Cable to the AUI Port

LTR-T Installation Guide 9
5. Connect the power cord to the LTR-T. The LTR-T can accept power from
either 110 Vac or 220 Vac outlets directly, therefore, there is no need to use a
voltage adapter.
Warning:
To reduce the risk of electric shock, in countries using an IT
power system or where protective earth ground connection is
not made, the ground conductor of the power cable should be
connected to earth ground.
6. Turn the repeater on. The LTR-T should automatically begin the self-test
procedure, described in the next section, to check the status of the hardware. If no
LEDs come on, refer to the “Testing and Diagnostics” section for troubleshooting
suggestions.
Adding New Network Segments
It is not necessary to remove power to the LTR-T when adding new segments to an
existing network. However, adding or removing an existing connection may disrupt the
transmission of an individual Ethernet packet. It is the intent of the IEEE Ethernet
specification that this be a recoverable error at the software level.
To add a new segment to the LTR-T, simply connect the new segment to the LTR-T port.
If there are no faults on the new segment, the LTR-T will automatically integrate the
segment into the existing network.

10 LTR-T Installation Guide
Power-up Sequence
This section explains the LTR-T power-up diagnostics and interpretation of the LED
display during normal operation. At the end of this section you will find suggestions for
troubleshooting problems with the unit as well as maintenance information.
LED Test
Upon turning on the LTR-T you will observe the power-up LED test sequence. The
status (STAT) LEDs will display a sequence of green, yellow, and red LEDs while a
single green LED follows along in the activity (ACT) row(s) of LEDs. The collision
(COL) LED should be red during this pattern. If the LEDs do not behave in this manner
then please refer ahead to the section on Troubleshooting.
Firmware Version
After the testing the LEDs, the LTR-T will display the firmware version of your LTR-T
unit. This display will last approximately 3 seconds and is indicated by all green STAT
LEDs. The firmware version will be displayed by the ACT LEDs numbered one (1)
through eight (8) in a binary format. A lit LED corresponds to a one (1) in that bit
position while an unlit LED corresponds to a zero (0) in that bit position. For example,
version 1.3 will be displayed as
(0) (0) (0) (1) (0) (0) (1) (1)
off off off green off off green green
Diagnostics
After displaying the firmware version, the LTR-T will display the results of the power-up
diagnostics tests if any type of failure was detected. Otherwise, the LTR-T will proceed
directly to status mode.
Diagnostic display mode is indicated by either all yellow or all red STAT and power
(PWR) LEDs. The diagnostic code is displayed using the ACT LEDs in a similar manner
as described above in the section on Firmware Version. In addition, the COL LED
contains information that may be useful in diagnosing problems with your LTR-T. Please
refer to Table 3 for a description of the diagnostic codes.
1. The AUI-ACT LED should be off. The COL LED will be red if the unit is an
LTR-16T; the LED will be off if it is an LTR-8T. If the COL LED does not
reflect the true hardware type, it may indicate a hardware fault. Try cycling
power to the hub and see if the indication persists. If so, contact your dealer or
Lantronix.
2. The diagnostic results will be shown on the upper right 9 LEDs - Table 3 explains
the meaning of the LED colors.

LTR-T Installation Guide 11
STAT LEDs Explanation
YELLOW LTR-T is powering-up to the factory default configuration.
This is expected if during power-up both front panel buttons
were pressed. Otherwise, this display indicates that the non-
volatile RAM (NVR) has failed and the unit should be returned
to Lantronix for servicing.
0000 0001 - NVR checksum error - power-up defaults used.
0000 0010 - User requested power-up defaults.
RED LTR-T failed power-up diagnostics. The ACT LEDs indicate
the diagnostic code in binary format:
0000 0001 - Upper board failure (LTR16T).
0000 0010 - NVR failure.
0000 0100 - Inter-board communication failure (LTR16T).
Having failed power-up diagnostics, the LTR-T will disable all
ports and continue to display the diagnostic code indefinitely.
Lantronix or your dealer should be contacted.
Table 3: Power-up Diagnostic Codes
Upon successfully completing the power-up diagnostics, the LTR-T will begin normal
operation in status mode as indicated by the following LED displays:
1. The power LED blinks green.
2. The status of the AUI and UTP ports is displayed by their corresponding STAT
LEDs (see Table 4, below, for a description of the port STAT LEDs.)
3. Port activity is indicated by the corresponding ACT LEDs.
4. Network collisions are indicated by the COL LED.

12 LTR-T Installation Guide
Troubleshooting
If your LTR-T unit does not power-up properly, try the following:
1. Check the power cable. Verify that power is reaching the unit. The LTR-T can
receive power from either 110 Vac or 220 Vac outlets without any modification
to the hardware, however, you must make sure the unit is properly grounded.
2. Check that the LEDs light when the POWER switch is turned on. If they do
not light, check the fuse on the back of the unit to make sure that it is not blown.
3. Check that the LTR-T successfully completes the Power-Up diagnostics. The
Power-Up diagnostics are described earlier in this section. Refer to Table 3 for an
explanation of the LEDs displayed during the test.
If these suggestions do not help, please contact your dealer.

LTR-T Installation Guide 13
Normal Operation
During normal operation the LTR-T displays the status and activity of all its attached
ports. The each port’s status is displayed as follows:
STAT LED Explanation
GREEN UTP ports
AUI ports
The link is good and receive polarity is correct.
or
the link test function and/or polarity correction is disabled.
The attached transceiver is functioning normally
or
the AUI port does not have a transceiver attached.
YELLOW UTP ports The LTR-T has detected reversed receive wires on this port and
is correcting the polarity before retransmitting the data. (Note:
if polarity correction is disabled, the LTR-T will neither check
nor correct the polarity of the data before retransmitting.)
RED UTP ports
AUI ports
The port is failing the link test if the test is enabled
and/or
the port has been automatically partitioned from the network
due to excessive collisions.
(Note: ports which have link test enabled, but are not connected
to a device at the opposite end of the segment will fail the link
test.)
The port has been automatically partitioned from the network
due to excessive collisions. In this state the port continues to
transmit, but receive data and collisions are ignored until the
LTR-T is able to determine that the segment is no longer bad.
(Note: if the AUI port is connected to a Thickwire/Thinwire
segment that is not terminated properly, the port will be
partitioned by the LTR-T.)
Blinking UTP and
AUI ports The port was auto-partitioned out (due to line errors) and subsequently reinstated and is operating normally. The blinking
can be stopped by pressing the left MODE button.
Off UTP and
AUI ports The port has been manually partitioned from the network by the user and is not capable of transmitting or receiving data (see the
section on Configuration for more information.)
Table 4: Explanation of Port Status LEDs

14 LTR-T Installation Guide
Configuration
The LTR-T has several features, configurable via the front panel:
1. Link test - Enabled on all UTP ports by default, the link test function
continuously checks the ports to verify that a proper connection exists between
each port and the device at the opposite end of the UTP cable. In order for the
link test function to pass, the device at the opposite end of the UTP cable must
support link test functionality. For proper functioning of the network, the link test
function must be disabled on all ports connected to devices that do not support the
link test function.
2. Polarity correction - Enabled on all UTP ports by default, the polarity correction
feature allows the LTR-T to detect reversed receive wires on the UTP cable by
monitoring the polarity of the incoming data. The LTR-T then corrects the
polarity of the data prior to retransmitting it to the other ports. If polarity
correction is not enabled, the LTR-T will neither detect nor correct the polarity of
incoming packets prior to retransmitting them.
3. Manual partitioning - Disabled on all ports by default, manual partition allows
the user to prevent ports from transmitting data to or receiving data from the
attached segment (in effect disabling the port.)
(Note: the LTR-T will automatically partition from the network any port on
which it detects excessive collisions. This is different from disabling a port via
manual partitioning in that auto-partitioned ports are re-instated to the network as
soon as the LTR-T decides that the segment is no longer bad.)
4. Port reconnection - There are two methods by which the LTR-T may determine
when a port should be re-instated after being auto-partitioned. from the network.
By default, all ports are re-instated if the LTR-T is able to receive or transmit data
to an auto-partitioned port without detecting a collision. Optionally, the LTR-T
can be configured to an alternate, more stringent method, in which it reinstates
only those ports to which it is able to transmit data without detecting a collision.
In both cases, the data must be a minimum of 512 bits in length.
The following feature is not controlled via the front-panel buttons:
5. Hub-to-hub interconnection - In many cases it is necessary to interconnect
multiple LTR-Ts to provide more than 8 or 16 UTP connections to the network.
Ports 8 and 16 (LTR16T) are configurable to simplify the cabling effort when
interconnecting LTR-Ts (see the section below on Hub Interconnection.).