Black Box MT618A-ST-R2, MT619A-ST-R2 User Manual

CUSTOMER

SUPPORT

INFORMATION

Order toll-free in the U.S.: Call 877-877-BBOX (outside U.S. call 724-746-5500)
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax [phone]
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [e-mail]

SEPTEMBER 2002

MT618A-ST-R2
MT619A-ST-R2

T3 Fiber Optic Line Driver

1

FCC AND IC RFI STATEMENTS

FEDERAL COMMUNICATIONS COMMISSION

AND

INDUSTRY CANADA

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 manufacturer’s
instructions, may cause interference to radio 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 B 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.

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 Industry Canada.

Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites
applicables aux appareils numériques de la classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par Industrie Canada.

2

T3 FIBER OPTIC LINE DRIVER

NORMAS OFICIALES MEXICANAS (NOM)

ELECTRICAL SAFETY STATEMENT

INSTRUCCIONES DE SEGURIDAD

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 deberán ser guardadas para
referencia futura.

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

4. Todas las instrucciones de operación y uso deben ser seguidas.

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 recomendados por el fabricante.

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

8. Servicio—El usuario no debe intentar dar servicio al equipo eléctrico más allá
a lo descrito en las instrucciones de operación. Todo otro servicio deberá ser
referido a personal de servicio calificado.

9. El aparato eléctrico debe ser situado de tal manera 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 de fuentes de calor
como radiadores, registros de calor, estufas u otros aparatos (incluyendo
amplificadores) que producen calor.

11. El aparato eléctrico deberá ser connectado a una fuente de poder sólo del
tipo descrito en el instructivo de operación, o como se indique en el aparato.

3

NOM STATEMENT

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

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

4

T3 FIBER OPTIC LINE DRIVER

TRADEMARKS USED IN THIS MANUAL

ST is a registered trademark of American Telephone and Telegraph Company.

Any other trademarks mentioned in this manual are acknowledged to be the property of the
trademark owners.

5

CONTENTS

Contents

Chapter Page

Quick Start Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

2.1.1 Versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

2.1.2 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

2.1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.1.4 Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

2.2 Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

2.3 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

2.3.1 Signal Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

2.3.2 Data/Clock Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

2.3.3 Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

3. Installation and Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.1 Site Requirements and Prerequisites . . . . . . . . . . . . . . . . . . . . . . .14

3.2 What the Package Includes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.3 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

3.3.1 Setting the Internal Jumpers . . . . . . . . . . . . . . . . . . . . . . . .15

3.3.2 Connecting the Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . .19

3.3.3 Connecting the Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

4.1 Front-Panel Indicators and Controls . . . . . . . . . . . . . . . . . . . . . . .21

4.2 Operating the Line Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

4.2.1 Powering On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

4.2.2 Normal Operating Instructions . . . . . . . . . . . . . . . . . . . . . .22

4.2.3 Powering Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

5. Diagnostics and Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.1 Alarm Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.2 Diagnostic Loopbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

5.2.1 Local Loopback (LLB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

5.2.2 Remote Loopback (RLB) . . . . . . . . . . . . . . . . . . . . . . . . . . .24

5.3 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.4 Calling Black Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

5.5 Shipping and Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

6

T3 FIBER OPTIC LINE DRIVER

Quick Start Guide

If you’re familiar with the T3 Fiber Optic Line Driver, use this guide to prepare the
unit for operation.

Installation

Open the T3 Fiber Optic Line Driver’s case by unscrewing the two rear-panel
screws and sliding out the unit’s printed circuit board (PCB).

S

ETTING THEINTERNALJUMPERS

Set the main board jumper according to the following table:

Jumper Description Values Factory Setting

JP2 Controls the AIS On—AIS is On

transmission to the transmitted.
electrical or optical Off—AIS is
interface when a minor not transmitted.
alarm is detected.

S

ELECTING THE

T3 C

ABLELENGTH

Refer to the table below and select the cable length.

T3 Cable Length Jumper Positions

JP1 JP2 JP3

Up to 225 ft. Pins 2, 3* Pins 1, 2* Pins 2, 3*
226 ft. to 450 ft. Pins 1, 2 Pins 1, 2 Pins 1, 2
More than 450 ft. Pins 1, 2 Pins 2, 3 Pins 1, 2

*Factory settings.

NOTE

The maximum cable length complies with ITU-T G.703.

Slide the circuit board back into the case and replace and tighten the screws.

7

QUICK START GUIDE

C

ONNECTING THE

C

ABLES

1. Connect the T3 electrical interface.

2. Connect the fiberoptic interface.

3. Connect the power cable (first to the modem, then to the mains supply).
Operation starts when the power is applied to the rear-panel power
connector.

Operation

1. Check that the TEST switch is set to the NORM position.

2. Verify LED status. The POWER LED should be on; all other indicators should
be off.

3. If there is an indication of a malfunction or fault, run a diagnostic test.

8

T3 FIBER OPTIC LINE DRIVER

1. Specifications

T3 Electrical Interface

Transmission Rates: 44.736 Mbps
Impedance: 75 Ω unbalanced
Zero Suppression: B3ZS
Connectors: (2) BNC

Fiberoptic Interface

Operating Wavelength: MT619A-ST-R2: 850 nm (multimode);
MT618A-ST-R2: 1310 nm (single-mode)

Line Coding: CDP
Connectors: (2) ST

®

Typical Power: See Table 2-1
Receiver Sensitivity: See Table 2-1
Range: See Table 2-1

Diagnostics

Loopbacks: Local loopback (LLB), activated via front-panel slide switch;
Remote loopback (RLB), activated via front-panel slide switch

AIS Signaling: Frequency of ±25 ppm is sent to the electrical interface at the local
unit in the event of an optical signal loss; when the electrical interface input level is
“LOW,” “All 1s” signaling is sent to the optical output

Alarm Relay Port

Connector: (1) DB9 female
Alarms: Major: T3 electrical input becomes lower than G.703 electrical levels, or bit

error rate at the fiberoptic interface is 10

-6

or worse; Minor: Alarm Indication

Signal (AIS) is received at the T3 electrical or fiberoptic interfaces

9

CHAPTER 1: Specifications

Operation: Normally Open and Normally Closed, using different pins

Indicators

POWER: Power
LOC: A local loopback is active
REM: A remote loopback is active
ELECTRICAL LOW: T3 electrical input is below G.703
ELECTRICAL AIS: T3 electrical interface received “All 1s” string
OPTICAL ERR: Bit error rate of the signal received from the optical interface is

10

-6

or worse

OPTICAL AIS: Fiberoptic interface received “All 1s” string

Power

AC Source: 100 to 240 VAC, 50/60 Hz

Physical

Size: 1.7"H x 7.6"W x 9.6"D (4.3 x 19.3 x 24.4 cm)

Environment

Temperature: 32 to 113°F (0 to 45°C)
Humidity: Up to 90%, noncondensing

10

T3 FIBER OPTIC LINE DRIVER

2. Introduction

2.1 Overview

The T3 Fiber Optic Line Drivers are fiberoptic modems for transmission of T3
(44.736 Mbps) over multimode or single-mode fiberoptic media. The line drivers
are transparent to framing and can transmit data using any framing pattern with
B3ZS coded signals.

Conversion of the electrical signal into an optical signal is achieved using an
infrared light-emitting diode. At the opposite end of the fiber, the optical signal is
converted back into an electrical signal and amplified to the required level.

The T3 Fiber Optic Line Drivers use a Phase Locked Loop (PLL) circuit electrical
interface (on BNC connectors with 75 Ω impedance) to recover data and clock
from the signal.

Diagnostic and alarm features include LED status indicators, V.54 loopback
activated from the front panel, and supervisory port for reporting system status.

2.1.1 V

ERSIONS

Two versions are available:

• T3 Fiber Optic Line Driver ST, 1310-nm Single-Mode (MT618A-ST-R2)

• T3 Fiber Optic Line Driver ST, 850-nm Multimode (MT619A-ST-R2)

2.1.2 A

PPLICATION

In the application shown in Figure 2-1, each line driver receives T3 signals, which
are equalized to overcome electrical link distortion. The line driver converts the T3
signal into an optical signal.

Figure 2-1. Typical application.

Fiber Optic

FOM-T3/E3

CoaxCoax

FOM-T3/E3

T3 or E3

T3 or E3

T3/E3

MUX

T3/E3

MUX

Up to 68.35

miles (110 km)

T3 Mux

T3 Mux

Line

Driver

Line

Driver

T3

T3

11

CHAPTER 2: Introduction

2.1.3 F

EATURES

• Extend the range of T3 signals over fiberoptic cable up to 68.35 miles
(110 km).

• Transparent to T3 signals.

• Conform with all relevant ITU series standards.

• Supports single-mode or multimode fiber.

• LED status indicators.

• V.54 loopbacks activated from the front panel.

• An alarm relay port for reporting the status of the system.

• Immunity to electrical interference such as EMI, RFI, spikes, and differential
ground loops.

• Secure data transfer (no tapping on the transmitted information).

• Protection from sparks and lightning.

• Secure link in hazardous or hostile environment.

Table 2-1. Fiberoptic interface options.

Wave- Fiber Type Transmitter Typical Receiver Maximum
length Type Power Sensi- Range

tivity

[nm] [µm] [dBm] [km/miles]

850 62.5/125 multimode LED -18 -28 2.5/1.5

1310 9/125 single-mode LED -15 -31 27/16.8

2.1.4 A

LARMS

When the T3 Fiber Optic Line Driver detects that electrical interface levels are
below G.703 electrical levels, it transmits an “All 1s” signal (AIS) to the optical
interface.

When an AIS is detected at the optical or electrical interface, the line driver
transparently converts the signal and alerts the user via the front-panel LEDs and
the alarm relay port.

12

T3 FIBER OPTIC LINE DRIVER

Likewise, an alarm is relayed if a high bit-error rate is detected at the fiberoptic
interface.

2.2 Physical Description

Figure 2-2. The front panel.

The line driver’s front panel features LEDs that display T3 electrical and fiberoptic
interface status. The front panel also includes a POWER LED and a TEST slide
switch for local- and remote-loopback activation. For details, refer to Chapter 4.

The rear panel has an AC power connector, a T3 electrical interface connector,
fiberoptic connectors, and an alarm relay connector. The rear panel is shown in
Figure 3-3 (in Chapter 3).

13

CHAPTER 2: Introduction

2.3 Functional Description

Figure 2-3. T3 Fiber Optic Line Driver block diagram.

The T3 Fiber Optic Line Driver has the following signal-processing modules:

• Signal conversion (see Section 2.3.1)

• Data/clock recovery (see Section 2.3.2)

• Data transfer (see Section 2.3.3)

2.3.1 S

IGNALCONVERSION

Conversion of the electrical NRZ (non-return to zero) signal into an optical CDP
signal is performed by an infrared light-emitting diode. At the opposite end of the
fiber, the optical signal is converted back into an electrical signal and amplified to
the required level.

2.3.2 D

ATA/CLOCKRECOVERY

To recover data and clock from the signal, a Phase Locked Loop (PLL) circuit is
used. The line driver provides internal selection for the T3, 75Ω balanced, B3ZS
line coding electrical interface.

2.3.3 D

ATATRANSFER

The optical signal is linked to the fiberoptic media and transmitted via the optical
link to the remote unit. A high-sensitivity pre-amplifier and an AGC (Automatic
Gain Control) circuit enable the remote unit to receive the optical signal. The
output of the receiver is applied to the clock recovery circuit and data regeneration
circuit, which in turn applies it to the electrical interface driving circuit.

T3 Electronic

Interface

BNC

connectors

Fiberoptic

connectors

14

T3 FIBER OPTIC LINE DRIVER

3. Installation and Setup

WARNING

Internal settings, adjustment, maintenance, and repairs should be
performed only by a skilled technician who is aware of the hazards
involved.

Always observe standard safety precautions during installation,
operation, and maintenance of this product.

3.1 Site Requirements and Prerequisites

Install the line driver within 5 ft. (1.5 m) of an easily-accessible grounded AC outlet
capable of furnishing the required supply voltage.

Allow at least 36" (91.4 cm) of frontal clearance for operator access and at least 4"
(10.2 cm) clearance at the rear of the unit for interface cable connections.

The ambient operating temperature of the line driver should be 32 to 113°F (0 to
45°C) at a relative humidity of up to 90%, noncondensing.

3.2 What the Package Includes

Your package should include the following items:

• T3 Fiber Optic Line Driver

• AC power cord

• This users’ manual

If anything is missing or damaged, please contact Black Box at 724-746-5500.

3.3 Installation

The line driver is a standalone device intended for tabletop or bench installation.
It is delivered completely assembled. No provision is made for bolting the line
driver to the tabletop.

To install the line driver, you will:

1. Determine the required configuration of the line driver according to your
application. Set the internal jumpers and switches accordingly (see Section

3.3.1).

15

CHAPTER 3: Installation and Setup

2. Connect the T3 electrical interface (see Section 3.3.2).

3. Connect the fiberoptic interface (see Section 3.3.2).

4. Connect power to the line driver.

3.3.1 S

ETTING THE

I

NTERNALJUMPERS

This section provides information on the functions of the line driver’s jumpers and
gives step-by-step instructions for performing the internal settings. The default
settings are also listed.

Locations of jumpers and switches

The T3 Fiber Optic Line Driver includes three printed circuit boards: the main
board, the T3 interface board, and the fiberoptic interface board (see Figures 3-1
and 3-2).

The main board contains the common signal-processing circuits. One jumper
(JP2) is provided for user settings.

The T3 interface board provides connection to the T3 link. The T3 board contains
jumpers for selecting the T3 cable length.

The fiberoptic interface board provides connection to the fiberoptic cable. The
fiberoptic board does not contain any jumpers or switches.

Opening the case

To reach the line driver’s internal jumper and switch, you’ll need to open its case.

WARNING

Only authorized and qualified service personnel should open the line
driver.

To avoid accidental electric shock, always disconnect the interface
cables and the power cord before opening the line driver.

Line voltages are present inside the line driver when it is connected to
power and/or to the lines. Moreover, under external fault conditions,
dangerous voltages may appear on the lines connected to the units.

Any adjustment, maintenance, and repair of the opened equipment
under voltage should be avoided as much as possible and, when
absolutely necessary, should be carried out only by a skilled technician
who is aware of the hazard involved. Capacitors inside the instruments
may still be charged even after the instruments have been disconnected
from their power source.

16

T3 FIBER OPTIC LINE DRIVER

CAUTION

The T3 Fiber Optic Line Driver contains components sensitive to
electrostatic discharge (ESD). To prevent ESD damage, avoid touching
the internal components. Before moving jumpers, touch the line driver’s
frame.

To open the line driver’s case, unscrew the two rear-panel screws and slide out the
line driver’s printed circuit board.

Setting the main board internal jumpers

The internal jumper located on the line driver’s main board is shown in Figure 3-1.
The jumper settings are described in Table 3-1.

17

CHAPTER 3: Installation and Setup

Figure 3-1. Main board layout.

T3 Interface Board

18

T3 FIBER OPTIC LINE DRIVER

Table 3-1. Main board jumper settings.

Jumper Description Values Factory Setting

JP2 Controls the AIS On—AIS is transmitted. On

transmission to the Off—AIS is not
electrical or optical transmitted.
interface when a
minor alarm is
detected.

Setting the T3 interface board jumpers

The line driver’s T3 interface board features jumpers (JP1–JP3) that are used for
selecting the T3 cable length. See Figure 3-2 and Table 3-2.

Figure 3-2. T3 interface board layout.

Table 3-2. Selecting the T3 interface cable.

T3 Cable Length Jumper Positions

JP1 JP2 JP3

Up to 225 ft. Pins 2, 3* Pins 1, 2* Pins 2, 3*
226 ft. to 450 ft. Pins 1, 2 Pins 1, 2 Pins 1, 2
More than 450 ft. Pins 1, 2 Pins 2, 3 Pins 1, 2

*Factory settings.

19

CHAPTER 3: Installation and Setup

NOTE

The maximum cable length complies with ITU-T G.703.

Closing the case

Once you finish the internal settings, close the line driver’s case.

1. Slide the printed circuit board back into the case.

2. Screw in the two rear-panel screws that fasten the main board to the case.

3.3.2 C

ONNECTING THE

I

NTERFACES

Figure 3-3 shows the line driver’s rear panel.

Figure 3-3. Rear panel.

Connecting the T3 interface

The line driver’s T3 interface is terminated in two BNC coax connectors,
designated In and Out.

1. Connect the receive line by attaching a 75Ω coaxial cable to the BNC
connector labeled In.

2. Connect the transmit line by attaching a 75 Ω coaxial cable to the BNC
connector labeled Out.

ALARM

ELECTRICAL

OUT IN

OPTICAL

TX RX

LINE FUSE

20

T3 FIBER OPTIC LINE DRIVER

Connecting the fiber optic interface

The line driver’s fiberoptic interface is terminated in ST connectors (TX and RX).

1. Remove the connectors’ protective caps and store them in a safe place for
later use.

2. Connect the transmit fiber to the TX connector and the receive fiber to the
RX connector.

3. At the remote unit, connect the transmit fiber to the RX connector and the
receive fiber to the TX connector.

3.3.3 C

ONNECTING THE

P

OWER

WARNING

The line driver has no power switch. Operation begins when the power
is applied to the Power connector.

Before switching on the line driver and connecting any other cable, the
line driver’s protective earth terminals must be connected to the mains
power cord’s protective ground conductor. If you are using an extension
cord (power cable), make sure it is grounded as well.

Any interruption of the protective (grounding) conductor (inside or
outside the instrument) or disconnecting of the protective earth terminal
can make this unit dangerous. Intentional interruption is prohibited.

Make sure that only fuses of the required rating (as marked on the rear
panel) are used for replacement. Do not use repaired fuses or short­circuit the fuse holder. Always disconnect the mains cable before
removing or replacing the fuse. Whenever it is likely that the fuse
protection has been damaged, make the unit inoperative and secure it
against unintended operation.

Connecting the AC power

AC power should be supplied to the line driver through the included 5-ft. (1.5-m)
standard power cable terminated by a standard 3-prong plug.

Connect the power cable first to the connector on the line driver’s rear panel, then
to the mains outlet.

The line driver will power on automatically upon connection to the mains.

21

4. Operation

4.1 Front-Panel Indicators and Controls

The indicators on the front panel can be seen in Figure 4-1. The functions of these
indicators are described in Table 4-1. LEDs are called out with numbers and
switches are called out with letters.

Figure 4-1. Front-panel indicators.

Table 4-1. Indicator functions.

Name Type Function

1. Power Green LED On—Line driver is powered up.

2. Loc Yellow LED On—A local loopback is active.

3. REM Yellow LED On—A remote loopback is active.

A. Test Slide switch Controls the local and remote

loopbacks.

4. ELECTRICAL Low Red LED On—T3 electrical input is below G.703.

5. ELECTRICAL AIS Yellow LED On—T3 electrical interface received
“All 1s” string.

PWR

ERR

AIS

LOW AIS

LOC

NORM

REM

OPTICAL

ELECTRICAL

TEST

1 2 A 3 4 56

7

CHAPTER 4: Operation

POWER

22

T3 FIBER OPTIC LINE DRIVER

Table 4-1 (continued). Indicator functions.

Name Type Function

6. OPTICAL ERR Red LED On—Bit-error rate of the signal
received from the optical interface is
10-6or worse.

7. OPTICAL AIS Yellow LED On—Fiberoptic interface received
“All 1s” string.

4.2 Operating the Line Driver

4.2.1 P

OWERINGON

The line driver starts operating as soon as it is connected to the power source. The
POWER LED turns On and remains lit as long as the line driver is connected to
the mains.

4.2.2 N

ORMALOPERATINGINSTRUCTIONS

1. Check that the TEST switch is set to the NORM position.

2. Verify LED status. During normal operation, the POWER indicator should be
On; all others should be Off.

NOTE

Some of the LEDs may turn on when the line driver is powered up,
indicating that other communication equipment is not functioning
properly.

3. If there is an indication of a malfunction or fault, run a diagnostic test.

4.2.3 P

OWERINGOFF

Turn the line driver off by disconnecting the power cord from the mains.

23

5. Diagnostics and Troubleshooting

5.1 Alarm Relay

The T3 Fiber Optic Line Driver includes a dry-contact alarm-relay port for most
major and minor alarms.

• Major alarms are initiated when a) T3 electrical input becomes lower than
G.703 electrical levels or b) bit-error rate at the fiberoptic interface is 10

-6

or

worse.

• Minor alarms occur when an Alarm Indication Signal (AIS) is received at the
T3 electrical or fiberoptic interfaces.

The dry-contact port operates as Normally Open or Normally Closed. See the
pinout below.

Figure 5-1. Alarm relay connector pinout.

NOTE

The relay positions are shown in the non-energized state (alarm active).

CHAPTER 5: Diagnostics and Troubleshooting

KEY: In Figure 5-1, NO=Normally Open and NC=Normally Closed.

24

T3 FIBER OPTIC LINE DRIVER

5.2 Diagnostic Loopbacks

5.2.1 L

OCALLOOPBACK

(LLB)

Local loopback tests the performance of the T3 electrical interface of the local line
driver and the equipment attached to it.

The data received at the T3 electrical interface is looped back to the line driver
attached to it (see Figure 5-2).

Figure 5-2. Local loopback illustrated.

To activate local loopback, s

lide the TEST switch to the LOC position. The LOC

indicator turns On and remains lit as long as the local loopback is active.

5.2.2 R

EMOTELOOPBACK

(RLB)

Remote loopback tests the performance of the local line driver’s T3 electrical and
optical interfaces and the remote line driver’s optical interface.

The data received at the remote line driver’s optical interface is transmitted to the
electrical interface and is simultaneously looped back to the local line driver (see
Figure 5-3).

LOC POSITION

COAX

T3/E3
BERT

FOM

T3/E3

T3 Fiber

Optic Line

Driver

T3 Fiber

Optic Line

Driver

25

CHAPTER 5: Diagnostics and Troubleshooting

Figure 5-3. Remote loopback illustrated.

To activate remote loopback, slide the local line driver’s TEST switch to the REM
position.

The remote line driver’s LOC indicator turns On and remains lit as long as the
remote loopback is active.

5.3 Troubleshooting

If a problem occurs, refer to Table 5-1 for troubleshooting procedures. Perform
the actions listed under Corrective Measures in the order given in the table until
the problem is corrected. If the problem is still not resolved, call Technical
Support as described in Section 5.4.

Table 5-1. Troubleshooting chart.

Trouble Symptoms Probable Cause Corrective Measures

POWER indicator is Off. No AC power. Verify that the power outlet is

providing the required power.

Make sure that both ends of the
power cable are connected
properly.

Blown fuse. Replace with a fuse of the correct

rating.

T3/E3
BERT

LOCAL FOM

T3/E3

REM POSITION

COAX FIBER

REMOTE

FOM

T3/E3

Remote T3
Fiber Optic
Line Driver

Local T3
Fiber Optic
Line Driver

T3 BERT

26

T3 FIBER OPTIC LINE DRIVER

Table 5-1 (continued). Troubleshooting chart.

Trouble Symptoms Probable Cause Corrective Measures

ELECTRICAL LOW One of the T3 Make sure that both ends of the T3
indicator is On. coaxial cables is coaxial cables are connected

defective or correctly and that the cables
disconnected. function properly.

Attached equipment Verify that the output levels of the
outputs do not equipment attached to the T3
comply with G.703 interface comply with G.703.
electrical levels.

JP2 is set incorrectly. Check the JP2 settings (see

Table 3-1).

ELECTRICAL AIS Attached equipment Check the equipment attached to
indicator is On. transmits “All 1s.” the T3 electrical interface; make

sure that the line driver is
transmitting real data.

OPTICAL ERR No optical connection.Make sure that both transmit and
indicator is On. receive fiber cables are properly

connected to the local and remote
units.

The optical budget Measure the optical loss over the
is low. fiber link and check that it meets

the product specifications.

OPTICAL AIS is On. The equipment Check the equipment attached to

attached to the the remote line driver.
remote unit
transmits “All 1s”
string.

27

CHAPTER 5: Diagnostics and Troubleshooting

Table 5-1 (continued). Troubleshooting chart.

Trouble Symptoms Probable Cause Corrective Measures

TEST LOC indicator The unit is in the Set the TEST switch to the
is On. local-loopback mode. NORM position.

TEST REM indicator. The unit is in the Set the TEST switch to the

remote-loopback NORM position.
mode.

5.4 Calling Black Box

If you determine that your T3 Fiber Optic Line Driver is malfunctioning, do not
attempt to alter or repair the unit. It contains no user-serviceable parts. Contact
Black Box at 724-746-5500.

Before you do, make a record of the history of the problem. We will be able to
provide more efficient and accurate assistance if you have a complete description,
including:

• the nature and duration of the problem.

• when the problem occurs.

• the components involved in the problem.

• any particular application that, when used, appears to create the problem or
make it worse.

5.5 Shipping and Packaging

If you need to transport or ship your T3 Fiber Optic Line Driver:

• Package it carefully. We recommend that you use the original container.

• If you are shipping the T3 Fiber Optic Line Driver for repair, make sure you
include everything that came in the original package. Before you ship, contact
Black Box to get a Return Authorization (RA) number.

1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax [phone]

© Copyright 2002. Black Box Corporation. All rights reserved.