Black Box LBH1500A User Manual

© Copyright 2005. Black Box Corporation. All rights reserved.

1000 PARK DRIVE • LAWRENCE, PA 15055-1018 • 724-746-5500 • FAX [phone]

LBH1500A-R3

Black Box LH1500 LBH1500AE-R3

July 2005

LBH1501A-R3

LBH1501AE-R3

BLACK BOX

[phone]

Crossover

Media Converter

100 Mb/s

LINK PW R LINK

RX

TX

BLAC K BO X

[phone]

Crossover

Media Converter

100 Mb/s

LINK PW R LINK

RX

TX

Fast Ethernet Media Converters

Black Box LH1500 Media Converters Installation and User Guide (08/05)

Black Box LH1500 Media Converters

Installation and User Guide

Trademarks

UL is a registered trademark of Underwriters Laboratories
Ethernet is a trademark of Xerox Corporation
All applied-for and registered trademarks are the property of their respective owners

Important: Black Box LH1500 Media Converters contain no user serviceable
parts. Attempted service by unauthorized personnel shall render any and all
warranties null and void. If problems are experienced with a Black Box
LH1500 Media Converter, consult Section 5, Troubleshooting, of this User
Guide.

©2005 Black Box Corporation

Black Box LH1500 Media Converters Installation and User Guide (08/05)

Contacting Black Box

Please use the mailing address and phone and fax numbers listed below:

Black Box Corporation

P.O. Box 12800

Pittsburgh, PA 15241

Phone: [phone]

Fax: [phone]

Black Box LH1500 Media Converters Installation and User Guide (08/05)

FCC STATEMENT

FEDERAL COMMUNICATIONS COMMISSION &

CANADIAN DEPARTMENT OF COMMUNICATIONS

RADIO FREQUENCY INTERFERENCE STATEMENTS

This equipment generates, uses, and can radiate radio frequency energy and if not installed and used
properly, that is, in strict accordance with the communication. It has been tested and found to
comply with the limits for a Class A computing device in accordance with the specifications in
Subpart J of Part 15 of FCC rules, which are designed to provide reasonable protection against such
interference when the equipment is operated in a commercial environment. Operation of this
equipment in a residential area is likely to cause interference, in which case the user at his own
expense will be required to take whatever measures may be necessary to correct the interference.

Changes or modifications not expressly approved by the party responsible for compliance could void
the user’s authority to operate the equipment.

Black Box LH1500 Media Converters Installation and User Guide (08/05)

This digital apparatus does not exceed the Class A limits for radio noise emission from digital
apparatus set out in the Radio Interference Regulation of the Canadian Department of
Communications.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de classe A prescrites dans le Règlement sur le brouillage
radioélectrique publé par le ministère des Communications du Canada.

__________________________________________________________

NORMAS OFICIALES MEXICANAS (NOM)

ELECTRICAL SAFETY STATEMENT

1. Todas las instrucciones de seguridad y operación deberán ser leídas antes de que el aparato
eléctrico sea operado.

2. Las instrucciones de seguridad y operación deberan ser guardadas para referencia futura.

3. Todas las advertencias en el aparato eléctrico y en sus instrucciones de operación deben ser

respetadas.

INSTRUCCIONES DE SEGURIDAD

Black Box LH1500 Media Converters Installation and User Guide (08/05)

Todas las instrucciones de operación y uso deben ser seguidas.

4.

5. El aparato eléctrico no deberá ser usado cerca del agua—por ejemplo, cerca de la tina de baño,
lavabo, sótano mojado o cerca de una alberca, etc..

6. El aparato eléctrico debe ser usado únicamente con carritos o pedestales que sean

reconnendados por el fabricante.

7. El aparato eléctrico debe ser montado a la pared o al techo sólo como sea recommendado por el

fabricante.

8. Servicio—El usuario no debe intentar dar sercicio al equipo eléctrico más allá a lo descrito en

las instrucciones de operatión. Todo otro servicio deberá ser referido a personal de servicio
calificado.

9. El aparato eléctrico debe ser situado de tal mannera que su posición no interfiera su uso. La

colocación del aparato eléctrico sobre una cama, sofá, alfombra o superficie similar puede
bloquea la ventilación, no se debe colocar en libreros o gabinetes que impidan el flujo de aire
por los orificios de ventilación.

10. El equipo eléctrico deber ser situado fuera del alcance du fuentes de calor como radiadores,

registros de calor, estufas u otros aparatos (incluyendo amplificadores) que producen calor.

11. El aparato eléctrico deberá ser connectado una fuente de poder sólo del tipo descrito en el

instrucivo de operación, o como se indique en el aparato.

12. Precaución debe ser tomada de mal manera que la tierra fisica y la polarización del equipo no

sea eliminada.

Black Box LH1500 Media Converters Installation and User Guide (08/05)

Los cables de la fuente de poder deben ser guiados de tal manera que no sean pisados ni

13.

pellizcados por objetos colocados sobre o contra ellos, poniendo particular atención a los
contactos y receptáculos donde salen del aparato.

14. El equipo eléctrico debe ser limpiado únicamente de acuerdo a las recommendaciones del

fabricante.

15. En caso de existir, una antena externa deberá ser localizada lejos de las lineas de energia.

16. El cable de corriente deberá ser desconectado del cuando el equipo no sea usado por un largo

periodo de tiempo.

17. Cuidado debe ser tomado de tal manera que objectos liquidos no sean derramados sobre la

cubierta u orificios de ventilación.

18. Servicio por personal calificado deberá ser provisto cuando:

A: El cable de poder o el contacto ha sido dañado; u
B: Objectos han caído o líquido ha sido derramado dentro del aparato; o
C: El aparato ha sido expuesto a la lluvia; o
D: El aparato parece no operar normalmente o muestra un cambio en su desempeño;o
E: El aparato ha sido tirado o su cubierta ha sido dañada.

Black Box LH1500 Media Converters Installation and User Guide (08/05)

TABLE OF CONTENTS Page

1.0 SPECIFICATIONS.................................................................................... 1

1.1. Technical Specifications *............................................................................ 1

1.2. Model numbers and product descriptions *.................................................. 5

2.0 INTRODUCTION ..................................................................................... 7

2.1 Inspecting the Package and Product............................................................... 7

2.2 Product Description *.................................................................................... 9

2.3 Features and Benefits ................................................................................... 13

2.4 Applications ................................................................................................. 15

3.0 INSTALLATION .................................................................................... 18

3.1 Locating the Media Converter Unit*............................................................ 18

3.2 Calculating Overall Segment Distance....................................................... 19

3.2.1 Segment Distances, Full-Duplex...................................................... 19

3.2.2 Segment Distances, Half-Duplex...................................................... 24

3.3 Connecting Fast Ethernet Media.................................................................. 33

3.3.1 Connecting Twisted Pair (RJ-45, TX).............................................. 33

3.3.2 Connecting Fiber-FX (SC-type “Snap-In”, and ST, "Twist-Lock") . 34

Black Box LH1500 Media Converters Installation and User Guide (08/05)

TABLE OF CONTENTS (CONTINUED) Page

3.3.3 Power Budget Calculations for Fiber media *.................................. 37

4.0 OPERATION........................................................................................... 39

4.1 Power requirements, power supply types *.................................................. 39

4.2 Front Panel LEDs - Black Box LH1500’s.................................................. 40

4.3 Up-Link Switch on TX port ......................................................................... 40

5.0 TROUBLESHOOTING........................................................................... 42

5.1 Before Calling for Assistance....................................................................... 42

5.2 When Calling for Assistance........................................................................ 44

5.4 Shipping and Packaging Information ......................................................... 45

* Changed in this revision

08/05 Added Power Budget Calculation for Fiber media.

05/99 (changed power supplies from a single model to separate models each
for 115vac 60Hz, and 230vac 50Hz).

Black Box LH1500 Media Converters Installation and User Guide (08/05)

1.0 SPECIFICATIONS

1.1. Technical Specifications

Performance:

Data Rate: 100 Mb/s
Half- or Full-Duplex, auto-sensing
800ns (80 bit-times) Path Delay Value (PDV) for conversion delay

Network Standards:

Fast Ethernet IEEE 802.3u: 100BASE-TX, 100BASE-FX

(Black Box LH1500 Media Converters are physical layer standard Fast

Ethernet products, and operate independently of all software.)

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Number of Media Converters in series:

Experience shows that up to three units can be used in series between

repeaters. For 4 or more in series, noise build-up will typically preclude
proper operation.

Maximum Standard Fast Ethernet Segment Lengths:
100BASE-TX (twisted pair): 100 m (328 ft)
100BASE-FX Fiber optic, half-duplex: (multi-mode) 412 m (1350 ft)
100BASE-FX Fiber optic, full duplex: (multi-mode) 2.0 km (6,562 ft)
100BASE-FX Fiber optic, half-duplex: (single-mode) 412 m (1350 ft)
100BASE-FX Fiber optic, full duplex: (single-mode) 15.0 km (49,215 ft)

Note:
shared Fast Ethernet segments. See Section 3.2 of this manual for
media lengths and shared segment distance calculations.

Black Box LH1500 Media Converters DO NOT support full length

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Operating Environment:

Ambient Temperature: 32ºF to 122ºF (0ºC to 50ºC)
Storage Temperature: -20ºC to 60ºC
Ambient Relative Humidity: 10% to 95% (non-condensing)

Power Supply (External):

Power Input: 95-125 vac at 60Hz

R2, LH1501A-R2” Models
200-250 vac at 50Hz

SC-R2, LH1500AE-ST-R2, LH1501AE-R2” Models

Power Consumption: 5 watts max. for the unit
Power output: +5VDC / 1000ma DO NOT USE A 12VDC P.S. UNIT

for “LH1500A-SC-R2, LH1500A-ST-

(or auto-ranging) for “LH1500AE-

Connectors:

RJ-45 Port: Modular 8-Pin female, with MDI-X up-link switch
Multi-mode:

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Fiber Port, SC-type (snap-in): Fiber optic multi-mode, 100BASE-FX
Fiber Port, ST-type (twist-lock): Fiber optic multi-mode, 100BASE-FX

Single-mode:
Fiber Port, SC-type (snap-in): Fiber optic single-mode, 100BASE-FX

Packaging:

Enclosure: High strength sheet metal.

Dimensions: 3.0 in H x 3.5 in W x 1.0 in D (7.6 cm x 8.9 cm x 2.5 cm)
Power Supply: 3.8 in x 1.5 in x 2 in (9.7 cm x 3.8 cm x 5.1 cm)
Weight: 9.5 oz. (275 gr); Power Supply 5.85 oz (166 gr)

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

LED Indicators for the Black Box LH1500’s and LH1501’s:
LED

PWR Indicates unit is receiving DC power.
LINK TP Fiber Steady ON when proper link is established

at both ends of the media segment, i.e.,
when both end’s connections are properly
made and when power is applied to the
devices on both ends of the segment.

Agency Approvals:

Power Supply is UL Listed (UL 1310), cUL
Emissions: Me e t s FCC Pa rt 15 Cla ss A, c UL

Made in USA

TX port FX port Description

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

1.2 Model Number Description
LH1500A-SC-R3 Twisted pair to mm fiber SC, ext. 115 vac, 60Hz power supply

LH1500AE-SC-R3 Twisted pair to mm fiber SC, ext. 230 vac, 50Hz power supply
LH1500A-ST-R3 Twisted pair to mm fiber ST, ext. 115 vac, 60Hz power supply
LH1500AE-ST-R3 Twisted pair to mm fiber ST, ext. 230 vac, 50Hz power supply
Single-mode:
LH1501A-R3 Twisted pair to fiber SC, single mode, ext. 115 vac, 60 Hz PS
LH1501AE-R3 Twisted pair to fiber SC, single mode, ext. 230 vac, 50 Hz PS

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

2.0 INTRODUCTION

This section describes the Black Box LH1500’s and LH1501’s Media

Converters, including appearance, features and possible applications.

2.1 Inspecting the Package and Product

Examine the shipping container for obvious damage prior to installing this
product; notify the carrier of any damage which you believe occurred during shipment or
delivery. Inspect the contents of this package for any signs of damage and ensure that
the items listed below are included.

This package should contain:
1 Black Box LH1500 Media Converter unit

1 External Power Supply, either 115 vac at 60Hz or 230 vac at 50Hz.
(Continued)

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

1 Set of two (2) metal mounting clips with screws

1 Velcro® Tape section, approximately 3 inches in length

Remove the Black Box LH1500 Media Converter from the shipping container.
Be sure to keep the shipping container should you need to ship the unit at a later date.

In the event there are items missing or damaged contact your supplier. If you
need to return the unit use the original shipping container. Refer to Section 5,
Troubleshooting, for specific return procedures.

Use the power supply provided, which has output at 5VDC
USE OF A 12VDC POWER SUPPLY WILL DAMAGE THE UNIT

only.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

2.2

Black Box LH1500 Media Converters offer a convenient and graceful way to
convert and transmit data among twisted pair and fiber network cabling environments.
They allow the use of fiber media with full-duplex devices such as Fast Ethernet
Switching Hubs, and may sometimes be used with shared (half-duplex) Fast Ethernet
segments as well. They offer a compact, cost-effective way to adapt a pre-existing
Ethernet cabling configuration as network requirements change.
Black Box LH1500 Media Converters are designed for quick and easy
installation even in very tight spaces. Media cables are easily attached. Black Box
LH1500 Media Converters feature an up-link switch on the TX port to eliminate the need
for a special cross-over cable when connecting the TX port to a hub or concentrator.
Because of their compact size, Black Box Media Converters can be Velcro®-mounted on
an office wall or the side of a desk or cabinet. The external power supply plugs into a

Product Description

9

Black Box LH1500 Media Converters Installation and User Guide (08/05)

nearby AC wall socket or power strip. Each converter features a full set of LEDs that
convey essential diagnostic and status information. See Section 4.1, LED Indicators, for
specific LED function information.

Black Box LH1500 Media Converters are designed to provide low-temperature
operation over an extended period to make them some of the most reliable in the
industry. Their high-strength fabricated metal packaging shields against Radio
Frequency Interference (RFI) and Electromagnetic Interference (EMI), avoiding
interference with other nearby electronic devices.

The Black Box LH1500 units comply with the IEEE 802.3u (100BASE-TX
and 100BASE-FX) specification for 100 Mb/sec traffic via shielded (STP) or unshielded
twisted pair (UTP) segments.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

The Black Box LH1500A-ST is equipped with one fiber-ST and one RJ-45
connector for connection to 100BASE-FX compliant networks segments.

Twisted Pair

(100BASE-TX)

Black Box LH1500

Media Converter

LINK

100 Mb/s

PWR

UP LINK

LINK

Fiber Multimode
(100BASE-FX)

(ST-type)

An LH1500A-ST-R2 integrates 100BASE-TX and FX networks, with fiber ST

connectors.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

The Black Box LH1500A-SC is equipped with one fiber-SC and one RJ-45
connector for connection to 100BASE-FX compliant networks segments.

Fiber

Twisted Pair

Black Box LH1500

(100BASE-TX)

An LH1500A-SC-R2 integrates 100BASE-TX and FX networks, with fiber SC
connectors.

Media Converter

LINK

100 Mb/s

PWR

UP LINK

12

(100BASE-FX)

(SC-type)

LINK

Black Box LH1500 Media Converters Installation and User Guide (08/05)

2.3 Features and Benefits

 Reduces Network Costs

Black Box LH1500 Media Converters offer an ideal solution to quickly
and inexpensively connect Twisted-Pair TX with Fiber FX segments.

 Full-duplex or Half-duplex operation, auto-sensing

LH1500s can be used in full-duplex fiber segments for distances up to
2Km for the multi-mode model, and up to 15Km for single-mode model.

 Low PDV for Maximum Cable Lengths in Shared Segments

Black Box LH1500 Media Converters add signal timing delays of only 80
Bit Times in a shared half-duplex segment, less than a Class II Fast
Ethernet Repeater (90 to 95 BT typical), and can be used to attach fiber
cable to TX ports with minimum distance loss in the collision domain.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

 Small, Compact, Lightweight Design

Featuring a compact and lightweight metal case with an external power
supply, Black Box LH1500 Media Converters can be conveniently
installed in minimal space, on horizontal or vertical surfaces.

 Full Complement of LEDs.

Each LH1500 Media Converter is equipped with a full complement of
LEDs to provide network LINK status on each port separately, and to
indicate power on the unit.

 Highly Reliable and Dependable

Black Box LH1500 Media Converters are based on a robust design and
packaged in a metal enclosures to ensure high reliability and durability.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

2.4

The primary function of Black Box LH1500 Media Converter is to permit two
different media types to coexist within the same network by allowing data to be
transmitted and received between different media types. Black Box 1500s are typically
used where new 100MB switching hubs with RJ-45 ports are being installed, and where
full-duplex fiber segments (of up to 2Km for multi-mode or 15Km for single mode) are
needed to interconnect them with other 100Mb switching hubs in distant wiring closets.
Alternatively, a server with a full-duplex NIC needs to be connected via fiber to a 100Mb
switching hub with RJ-45 ports. In these and similar situations, the Black Box LH1500
conveniently converts the twisted pair cable to fiber, allowing use of any available RJ-45
Fast Ethernet switched port with a new or existing fiber cable. See Section 3.2.1 for cable
distance calculation information.

Applications

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

100 BASE-TX

wiring segment

1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24

LH1500

Media Converter

UP LINK

100
Mb/s

LINK PWR

T

Two Black Box LH 150 0s provide conne ctivity for switch ch

100 BASE-FX

wiring segment

LINK

00

LH15

Media Converter

UP LINK

LINK

1 2 3 4 5 6 7 8 9 10
13 14 15 16 17 18 19 2 0 21 22

100
Mb/s

LINKPWR

T

11 12
23 24

100 BASE-TX

wiring segment

eded 100Mb hubs via fiber.

Where shared Fast Ethernet segments are used, such as with Fast Ethernet hubs

with RJ-45 ports, it may be desirable to connect one or more servers or users via fiber

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

cable. It is necessary to calculate the PDV of the overall collision domain (see Section

3.2.2) for proper operation when the LH1500 is used in shared half-duplex applications.

1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24

1 2 3 4 5 6 7 8 9 10 11 12

13 14 15 16 17 18 19 20 21 22 23 24
1 2 3 4 5 6 7 8 9 10 11 12
13 14 15 16 17 18 19 20 21 22 23 24

1 2 3 4 5 6 7 8 9 10 11 12

13 14 15 16 17 18 19 20 21 22 23 24

100 BASE-TX

wiring segment

17

LH1500

Black B ox

Media Converter

100

UP LINK

Mb/s

PWR

LINK

GARRET
T

100 BASE-FX

wiring segment

LINK

s or users via fiber.Black Box LH1500 provide s connectivity to server

Black Box LH1500 Media Converters Installation and User Guide (08/05)

3.0 INSTALLATION
This section describes the installation of the Black Box LH1500 Media
Converters, including location, segment distance calculation and media connection.

3.1 Locating the Media Converter Unit

The compact and lightweight design of the Black Box LH1500 Media
Converter allows it to be easily installed in most any location. A Velcro strip and a set of
two metal clips and screws are
included (either may be used) for
mounting the unit on a vertical surface
such as a wall or cabinet, or for
securing the unit on a table-top or
shelf. The installation location is
dependent upon the physical layout of
the Ethernet network and the cabling.

Secure attac

clips for wa

hment of mounting

ll mounting

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Make sure the unit is installed in a location that is easily accessible to an AC power
outlet or power strip, and where convection cooling is not inhibited.

3.2 Calculating Segment Distances

The media distance considerations are quite different for full-duplex and for
half-duplex (standard Fast Ethernet) installations. Each of these situations are covered
below in a separate section.

3.2.1 Segment Distances, Full-duplex
Full-duplex ports, such as are found in switching hubs and some NICs, can

receive and transmit signals simultaneously and do not experience collisions accordingly.
There may be only two nodes present on a full-duplex segment. Media distance rules are
not the same as for standard (half-duplex) Fast Ethernet because collision distance

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

limitations are not a factor. Specifically, fiber segments can be up to 2Km for multi­mode and up to 15Km for single mode.

The Black Box LH1500, with full-duplex operation as a standard feature, can
be used in these applications. When installing the Black Box LH1500 in a full-duplex
segment, it is important to consider the combined overall segment length of both of the
attached media types. The overall segment length is calculated by adding together the
segment lengths on both sides of the Black Box LH1500 Media Converters. The figure
below illustrates how a Black Box Media Converter is used to connect a multi-mode
fiber (100BASE-FX) with a twisted pair (100BASE-T) segment.

Segment length on each side of the LH1500 Media Converter is measured as a
percentage of the maximum allowable standard media distance for the given media type.
The percentages, when added together, must not exceed 100%.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Media Distance Formula for Black Box LH1500’s, full-duplex

X% + Y% <

Where X = The segment distance on one side of the Black Box LH1500
Media Converter divided by the Standard Maximum
Media Distance for that media type, x 100%

Where Y = The segment length on the other side of the Black Box LH1500
Media Converter divided by the Standard Maximum
Media Distance for that media cabling type, x 100%

100%

:

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Segment Y
10m (33ft)

Twisted Pair

Black Box

Media Converter

UP LINK

100 Mb/s

PWR

LINK

L

N

K

I

Segment X

1500m (4920ft)

Fiber Multimode

(100BASE-FX)

(100BASE-TX)

Connectivity between 100BASE-TX and 100BASE-FX Ethernet Media.

In the example figure shown above, the length of fiber Segment X is 1500m
(4920 ft). This is 75% of the maximum allowable distance for multi-mode 100BASE-FX
fiber full-duplex media (2000 m) [75/2000 x 100% = 75%]. The length of twisted pair
Segment Y is 10m (33 ft). This is 10% of the maximum allowable distance for

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

100BASE-TX full-duplex twisted-pair media (100 m) [10/100 x 100% = 10%]. The total
of the two percentages (75% + 10%) is 85%, which is allowable.

Note 1: Where more than one media converter is used in one

segment run, the percentages for all of the cabling lengths in the run

must be added together and must not exceed 100%.

In another instance, a Black Box Media Converter is used to connect a single
mode fiber (100BASE-FX) with a twisted pair (100BASE-T) segment. In this example,
the length of fiber Segment X is 8500m (27,880 ft). This is 57% of the maximum
allowable distance for single mode 100BASE-FX fiber full-duplex media (15,000 m)
[57/15,000 x 100% = 57%]. The length of twisted pair Segment Y is 12m (40 ft).

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

This is 12% of the maximum allowable distance for 100BASE-TX full-duplex twisted­pair media (100 m) [12/100 x 100% = 12%]. The total of the two percentages (57% +
12%) is 69%, which is allowable.

3.2.2 Segment Distances, Half-duplex

Fast Ethernet shared bandwidth devices operate with multiple nodes in a traffic
domain. When a node attempts to send a packet, it may hit another packet passing by,
i.e., a collision may occur. This is normal and does not cause a problem because the
Ethernet protocol provides for this situation and requires that the sender wait and try
again. When installing the Black Box LH1500 in a half-duplex segment, it is important
to consider the collision domain of the segment, including the LH1500 itself, repeaters
and hubs present, and the lengths of both of the attached media types.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Collision Domain

A collision domain is defined in the IEEE 802.3u standard as a cluster of
network devices that, regardless of topology, must be less than 512 BT (Bit Times) of
signal delay (PDV or Path Delay Value) in diameter between any two nodes. Nodes in a
collision domain are connected by means of a repeater or repeaters such that no bridging
or switching devices are present between any two nodes in the cluster. A Black Box
LH1500 has a PDV of about eighty Bit Times (80 BT), and this value must be included
in the overall collision domain diameter PDV calculations as applicable for the
placement of the LH1500 in the topology of the collision domain.

Collision Domain Diameter
The Collision Domain Diameter is the length of the longest path between any

two devices in a single collision domain. Regardless of the actual network topology, the

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Collision Domain Diameter must be less than 512 BT (Bit Times). Bit Times are related
to media type as shown in Table 3.2.2a.

Table 3.2.2a: Worst case round-trip delay for Fast Ethernet media*

Media Type Round-trip delay in

Bit Time per Meter (BT/m)
Fiber Optic
Shielded TP cable
Category 5 Cable
Category 4 Cable
Category 3 Cable

*Worst case delays taken from IEEE Std 802.3u-1995, actual delays may be less for a particular
cable. Contact your cable supplier for exact cable specifications.

Each shared Fast Ethernet network device also has an associated BT delay.
Table 3.2.2b shows typical Fast Ethernet device components and the associated BT
delay. Note that there is only one DTE pair associated with any device-to-device path.

1.000

1.112

1.112

1.140

1.140

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Table 3.2.2b: Worst case round-trip delay for Fast Ethernet device components*

Component Round-trip delay in Bit Times (BT)
2 TX DTEs
2 FX DTEs
1 FX and 1 TX DTE
2 T4 DTEs
1 T4 and 1 TX or FX DTE
Class I Repeater
Class II Repeater with any
combination of TX and FX ports
Class II Repeater with T4 ports

*Worst case delays taken from IEEE Std 802.3u-1995.

To determine whether a prospective network topology adheres to the collision
domain diameter specification, the following formula should be applied to the worst case
path through the network. The worst case path is the path between the two Fast Ethernet
devices (DTEs) which have the longest round trip delay time.

100
100
100
138
127
140

92

67

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

PDV = (sum of cabling delays) + (sum of repeater & media
converter delays) + (DTE pair delays) + (safety margin)

PDV is the Path Delay Value of the worst case path. For the network to adhere
to IEEE 802.3u standard, this value must be less than 512 BT. The safety margin is
specified in BT and may be a value between 0 and 5. This margin can be used to
accommodate unexpected delays, such as an extra long patch cable. A safety margin of
at least 4 BT is recommended.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

“Rules-of-thumb” Collision Domain Calculations

Rules-of-thumb, while inexact, may be helpful in planning network topology.
As a rule-of-thumb, a Class II Repeater has a PDV of about 90 to 95 BTs, and twisted­pair or fiber media has a PDV of about 1 BT per meter of length. The Black Box
LH1500 has a PDV of 80 BT. Therefore, in shared Fast Ethernet applications, the
LH1500 uses about 80 meters of equivalent cable distance to convert from TX media to
fiber FX media, i.e., it consumes almost as much of the available PDV as a Class II
repeater. Since a 512BT collision domain will almost always include at least one
repeater and two media segments, the remaining amount of Bit Times left after allowing
for a LH1500 and a length of fiber media indicates that the available fiber length will be
much less than the 412 meters that is the known maximum for fiber. Therefore, in shared
environments, Black Box LH1500 Media Converters will be of benefit when they allow

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

the use of fiber media, but not to gain distance by facilitating use of fiber media instead
of twisted pair.

As a sample calculation, consider the question of what fiber cable distance
(connected by a pair of Black Box LH1500 on each end) can be obtained that will
interconnect two 100Mb hubs where the twisted pair cables to the user nodes are 10
meters in length. The solution is :

512 = total available Bit Times in a collision domain diameter,

minus 100 BT for two DTEs on each end leaves 412 BTs,

minus 180 BT for two Class II repeaters leaves 232 BTs,

minus 20 BT for two 10-meter TP cables for hubs to users leaves 212 BTs,

minus 10 BT for two short TP cables from the hubs to 15E’s leaves 202 BTs,

minus 160 BT for two Black Box LH1500 leaves 42 BTs for fiber cable,

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

which indicates a fiber cable length of about 40 meters.
It is obvious that using twisted pair wiring to connect the hubs would enable the

interconnect length to be the 100 meters maximum for twisted pair media, and this would
still leave about a hundred BTs as a safety margin. In other words, use of LH1500s and
fiber in this case did not gain allowable maximum cable distance vs. TP cable without the
LH1500s.

Consider a more typical use of Black Box LH1500s in a shared Fast Ethernet
segment. A stack of Fast Ethernet hubs comprises the only repeater in the collision
domain, and the users and servers in the local workgroup are each connected via
Category 5 twisted pair cable, a maximum of 30 meters (100 ft.) in length. It is desired
to connect one remote user with a fiber NIC via fiber cable, using a LH1500 in the
circuit. How long can the fiber cable be?

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

The solution is :

512 = total available Bit Times in a collision domain diameter,

minus 100 BT for two DTEs on each end leaves 412 BTs,

minus 90 BT for one Class II stackable repeater leaves 322 BTs,

minus 30 BT for one 30-meter TP cable from hub to user node leaves 292 BTs,

minus 5 BT for a short TP cable from the hub to 15E leaves 287 BTs,

minus 80 BT for one LH1500 leaves 207 BTs for fiber cable,

which indicates a fiber cable length of about 200 meters

.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

3.3 Connecting Ethernet Media
Connecting Ethernet media to the Black Box LH1500 Media Converter is very
simple and straightforward. Using a properly terminated media segment, simply attach
the cable end to the appropriate connector.

See Sections 4.2 and 4.3 for a description of the LEDs.

3.3.1 Connecting Tw isted Pair (RJ-45, Unshielded or Shielded)
The following procedure describes how to connect a 100BASE-TX twisted pair

segment to the RJ-45 port on the Black Box LH1500 Media Converters. The procedure
is the same for both unshielded and shielded twisted pair segments.

1. Using standard 100BASE-TX media, insert either end of the cable with an RJ-45
plug into the RJ-45 connector of the Black Box LH1500 Media Converter.

2. Connect the other end of the cable to the corresponding device.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

3. Use the LINK LED to ensure proper connectivity by noting that the LED will be
illuminated when the unit is powered and proper connection is established. If
the LINK LED is not illuminated, change the setting of the up-link switch (See
Section 4.4 for up-link switch information.) If this does not help, ensure that the
cable is connected properly and is not defective.

3.3.2 Connecting Fiber Optic 100BASE-FX, Type ST and SC
The following procedure applies to 100BASE-FX applications using the Black

Box LH1500 Media Converter with ST-type (twist-lock) and SC-type (snap-in) fiber
connectors.

1. Before connecting the fiber optic cable, remove the protective dust caps from the
tips of the connectors on the Black Box LH1500. Save these dust caps for future
use.

2. Wipe clean the ends of the dual connectors with a soft cloth or lint-free lens
tissue dampened in alcohol. Make certain the connectors are clean before
connecting.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

Note: One strand of the duplex fiber optic cable is coded using color

bands at regular intervals; you must use the color-coded strand on

the associated ports at each end of the fiber optic segment.

3. Connect the Transmit (TX) port (light colored post) on the LH1500A to the
Receive (RX) port of the remote device. Begin with the color-coded strand of
the cable for this first “Transmit-to-Receive” connection.

4. Connect the Receive (RX) port (dark colored post) on the LH1500 to the
Transmit (TX) port of the remote device. Use the non-color coded fiber strand for
this.

5. The LINK LED corresponding to the fiber port on the front of the LH1500 will
illuminate when a proper connection has been established at both ends (and
when power is ON in the unit). If LINK is not lit after cable connection, the
normal cause is improper cable polarity . Swap the fiber cables on the LH1500
fiber connectors to remedy this situation.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

3.4.1 Pow er Budget Calculations for Fiber Media
Receiver Sensitivity and Transmitter Power are the parameters necessary to

compute the power budget. To calculate the power budget of different fiber media
installations, the following equations should be used:
OPB (Optical Power Budget) = P
where P

= Transmitter Output Power, and PR = Receiver Sensitivity

T

(min) - PR(min)

T

Worst case OPB = OPB - 1dB(for LED aging) - 1dB(for insertion loss)
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]
where the “Cable Loss” for 62.5/125 and 50/125

µm (m.m.) is 2.8 dB/km,

and the “Cable Loss” for 100/140 (multi-mode) is 3.3 dB/km,
and the “Cable Loss” for 9/125 (single-mode) is 0.5 dB/km

The following data has been collected from component manufacturer’s (Agilent’s) web
sites and catalogs to provide guidance to network designers and installers.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

R’cvr

Worst

Fiber

Port

Module

LH1500A

MST, MSC

LH1501A

Speed,

Std.

100Mb

FX

100Mb

FX

Mode

Multi-

mode

Single-

mode

Std. km

Wave-

Cable

X’mitr

fdx

length

(hdx)

2

(0.4)

25

(0.4)

Size

nm

µm

62.5/125

1300

50/125

1300 9/125 -15 -31 14 28 17.5 35

Output

dB

P

T ,

-20

-23.5

Sens.

P

R ,

-31

-31

dB

OPB,

dB

9.0

5.5

Worst*
distance
Km, fdx

2.5

2.0

typical

OPB,

dB

14
12

* Note: The use of either multi-mode or single-mode fiber to operate at 100Mbps speed
over long distances (i.e., over approx. 400 meters) can be achieved

only if the following

factors are both applied:

• The 100Mb fiber segment must operate in full-duplex (FDX) mode, i.e. a

switch (or equal external unit such as a FDX NIC) must be used, and

• The worst-case OPB of the fiber link must be greater than the fiber cable’s

passive Attenuation.

(Attenuation = Cable loss + LED aging loss + Insertion loss + safety factor)

37

typical*
distance
Km, fdx

5
4

Black Box LH1500 Media Converters Installation and User Guide (08/05)

4.0 OPERATION
This section describes the operation of the Black Box LH1500 Media

Converters including power supply requirements, up-link switch functionality, and a
description of all LEDs.

4.1 Power Requir e m e nts, Power Supply Types

Black Box LH1500 Media Converters require 5 watts of power and are designed to be
used with an external power supply.
two types; one version AC input power auto-ranging 115 vac at 60Hz for “LH1500A-SC­R2, LH1500A-ST-R2, LH1501A-R2” Models. The 115 vac version has a small
transformer integral with a convenience power outlet plug. The 230 vac at 50Hz version
for “LH1500AE-SC-R2, LH1500AE-ST-R2, LH1501AE-R2” Models. The 230 vac
version has a small transformer integral with an IEC-type power plug for a user-supplied
AC power cord with a convenience power outlet plug. Both type includes a lightweight
DC power cord to the applicable power jack on the Media Converter unit.

The external power supply unit supplied is one of

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

4.2 Front Panel LEDs
Description

LED
PWR Illuminates GREEN to indicate the unit is receiving DC power.
LINK (RJ-45 port) Illuminates GREEN, to indicate proper connectivity

on the 100BASE-TX network segment. LINK will turn off in the
event connectivity is lost between the ends of the twisted pair
segment or a loss of power occurs in the unit or remote device.

LINK (Fiber port) Illuminates GREEN, to indicate proper connectivity
on the 100BASE-FX network segment. LINK will turn off in the
event connectivity is lost between the ends of the fiber segment

4.3 Up-Link Switch (On TX port)

Black Box LH1500 Media Converters are equipped with an up-link slide
switch to accommodate repeater-to-converter connections without a special cross-over
cable. When set to the UP position (=), the Black Box LH1500 Media Converter is wired

or a loss of power occurs in the unit or remote device.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

for normal twisted pair connection to a user device. When set to the DOWN position
(X), the Media Converter is wired with cross-over functionality for direct up-link to a
network hub or concentrator.

up-link

user device

End view - Black Box L

()

)(

H1500

Up-link

Switch

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

5.0 TROUBLESHOOTING

If problems should develop during installation or operation, follow the
suggestions below prior to calling Technical Support for help. If you are unsure
of any procedure described in this chapter, or if the LH1500 Media Converter is
not operating as expected, do not attempt to repair or alter the unit. Contact
Black Box for assistance.

5.1 Before Calling for Assistance

1. If you have difficulty installing or operating the LH1500 Media Converter, refer

to Chapters 3 and 4. Make sure that the various other components of the
network are working.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

2. Check the cables and connectors to make sure that they have been properly

connected and the cables/wires have not been crimped or in some way impaired
during installation.

3. Check that the AC power cord is plugged into a functioning electrical outlet.

Make sure that the AC power cord is properly plugged into the LH1500. Use
the PWR LED to verify that the unit is receiving proper power.

4. If the problem is isolated to a network device other than the LH1500 Media

Converter, replace the problem device with a known good device. Verify
whether or not the problem is corrected. If it is not, go to step 5. If the problem
is corrected, the Ethernet Media Converter and its associated cables will
function properly.

5. If the problem still exists, contact Black Box.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

5.2 When Calling for Assistance

Please be prepared to provide the following information.

1. A complete description of the problem, including the following points:

a. The nature and duration of the problem;
b. Situations when the problem occurs;
c. The components involved in the problem;
d. Any particular application that, when used, appears to create the problem;

2. An accurate list of BLACK BOX product model(s)involved, with serial
number(s). Include the date(s) that you purchased the products from BLACK
BOX.

3. It is useful to include other network equipment models and related hardware,
including Convenient computers, workstations, terminals and printers; plus,
the various network media types being used.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

4. A record of changes that have been made to your network configuration prior

to the occurrence of the problem. Any changes to system administration

procedures should all be noted in this record.

5.3 Return Material Authorization (RMA) Procedure Shipping and Packaging Information

Should you need to ship the unit back to Black Box Corporation, please follow
these instructions:

1. Package the unit carefully. It is recommended that you use the original
container if available. Units should be wrapped in a "bubble-wrap" plastic
sheet or bag for shipping protection. ( You may retain all connectors and this
Installation Guide.)

CAUTION : Do not pack the unit in Styrofoam "popcorn" type packing

material. This material may cause electro-static shock damage to the unit.

2. Clearly mark the Return Material Authorization (RMA) number on the
outside of the shipping container.

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Black Box LH1500 Media Converters Installation and User Guide (08/05)

3. Black Box Corporation is not responsible for your return shipping charges.

4. Ship the package to:

Black Box Corporation
1000 Park Drive
Lawrence, PA 15055

Phone: [phone]

Fax: [phone]

45