Black Box ME375A-R2 User manual

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SUPPORT
INFORMATION
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MARCH 1998
ME375A-R2
ME375AE-R2
ME376A-R2
ME376AE-R2
Async/Sync 2-Wire Short Haul Modem
ASYNC/SYNC 2-WIRE SHORT HAUL MODEM
DIG ANA
PWR RTS TD RD DCD LOS ERR TEST REM PATT RESET

3
FCC/IC RFI STATEMENTS, SAFETY WARNING
FEDERAL COMMUNICATIONS COMMISSION
AND
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 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 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.
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 publié par le ministère des Communications du Canada.
SAFETY WARNING
Always observe standard safety precautions during installation, operation, and
maintenance of this product. If you attempt to remove the power-supply fuse, be
sure to disconect the power cord from the power source first, in order to avoid the
possibility of electric shock.

4
ASYNC/SYNC 2-WIRE SHORT-HAUL MODEMS
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 parato 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.

5
NOM STATEMENT
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.
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.

6
ASYNC/SYNC 2-WIRE SHORT-HAUL MODEMS
Contents
Chapter Page
1. Specifications ............................................................................................. 7
2. Introduction ............................................................................................. 10
3. Installation ................................................................................................ 11
3.1 Placement .......................................................................................... 11
3.2 Setting the Internal Controls ........................................................... 11
3.3 Connecting the Data Cables ............................................................. 16
3.4 Connecting to AC Power .................................................................. 17
4. Operation ................................................................................................. 19
4.1 The Front-Panel Controls and Indicators ....................................... 19
4.2 Power-Up, Normal Operation, and Power-Down ........................... 22
4.3 Reconfiguration ................................................................................ 23
5. Troubleshooting ...................................................................................... 24
5.1 Diagnostic Testing ............................................................................ 24
5.2 Calling Black Box .............................................................................. 28
5.3 Shipping and Packaging ................................................................... 28
Appendix: Pinouts .......................................................................................... 29
Legal Information ........................................................................................... 33

7
CHAPTER 1: Specifications
1. Specifications
Compliance — FCC Part 15 Subpart J Class A, DOC Class/MDC classe A
Standard — T1: ANSI T1.601.1988
Interfaces — ME375 models: 2-wire telco, EIA RS-232;
ME376 models: 2-wire telco, ITU-TSS (CCITT) V.35
Protocols — DTE side: Synchronous or asynchronous;
Line side: 2B1Q encoding
Clock Source — Internal, external (from DTE), or received (from other
unit), user-selectable
Data Format — 7 or 8 data bits; 1 or 2 stop bits; even, odd, or no parity
(user-selectable)
Operation — Line side: Full duplex with echo cancellation
Data Rate — 128, 115.2, 64, 57.6, 48, 38.4, 19.2, 9.6, 4.8, 2.4, 1.2, and
0.6 Kbps
Transmission
Level — Up to 14 dBm
Maximum
Distance — DTE side:
ME375 models: 50 ft. (15.2 m);
ME376 models: 25 ft. (7.6 m);
Line side: 3.4 mi. (5.5 km) over 26-AWG wire,
independent of data rate

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ASYNC/SYNC 2-WIRE SHORT-HAUL MODEMS
User Controls — (5) Front-mounted:
(4) Pushbuttons: DIG (local digital loopback), ANA
(local analog loopback), REM (remote digital
loopback), and PATT (test pattern);
(1) Recessed RESET switch;
(6) Internal:
(1) 7-position DIP switch for protocol, data format,
and signaling options;
(1) Rotary switch for data rate;
(4) Jumpers for clock source, loopback testing, and
ground connection
Diagnostics — V.54-compliant loopback tests:
Local analog loopback (switch- or signal-triggerable);
Local digital loopback (switch-triggerable);
Remote digital loopback (switch- or signal-triggerable)
Indicators — (8) Front-mounted LEDs: PWR (power), RTS, TD, RD,
DCD, LOS (loss of signal), ERR (error), and TEST
Connectors — ME375 models: (1) RJ-45 female, (1) 3-clip terminal
block, and (1) DB25 female;
ME376 models: (1) RJ-45 female, (1) 3-clip terminal
block, and (1) 34-pin M-block female
Leads/Signals
Supported — See the Appendix
Power — From internal power supply through included or
alternate 5-ft. (1.5-m) power cord:
ME375A-R2, ME376A-R2:
Input: 103.5 to 131.5 VAC, 47 to 63 Hz;
ME375AE-R2, ME376AE-R2:
Input: 207 to 253 VAC, 47 to 63 Hz;
Consumption: 5 VA

9
CHAPTER 1: Specifications
Fuse — ME375A-R2, ME376A-R2: 0.1-A slow-blow;
ME375AE-R2, ME376AE-R2: 0.2-A slow-blow
Other Power
Protection — AC/DC overvoltage-protection circuits connected
through transformers to transmit and receive leads on
the line side, plus special gas diodes
MTBF — 75,500 hours
Maximum
Altitude — 8000 ft. (2438.4 m)
Temperature
Tolerance — 32 to 122˚ F (0 to 50˚ C)
Humidity
Tolerance — Up to 90% noncondensing
Enclosure — High-impact plastic
Size — 1.8"H x 7.6"W x 9.6"D (4.6 x 19.3 x 24.3 cm), but the
unit’s pushbuttons protrude up to 0.1" (25 mm) from
the front panel and the connectors protrude up to 0.8"
(1.9 cm) from the rear panel
Weight — Net: 3.1 lb. (1.4 kg);
Shipping: 6 lb. (2.7 kg)

10
ASYNC/SYNC 2-WIRE SHORT-HAUL MODEMS
2. Introduction
The Async/Sync 2-Wire Short Haul Modem (A/S2W SHM) operates synchronously
or asynchronously at high speeds (600 bps to 128 Kbps) and in full duplex over
one pair of dedicated telephone lines. It has a range of 3.4 miles (5.5 km) over
26-AWG wire.
The A/S2W SHM operates in full duplex over 2 wires by using the adaptive
“echo-canceling” technique. Because it also uses 2B1Q line coding, it can achieve
the range mentioned above no matter what the data rate is.
The A/S2W SHM incorporates interface circuits for the terminal/computer, an
adaptive echo-canceler, an automatic adaptive equalizer, a modulator, and a
demodulator. It is coupled to the telephone line through an isolation transformer,
which protects against AC or DC overvoltages. The protection circuitry would
enable the unit to operate even if DC were accidentally connected to the line.
The A/S2W SHM has diagnostic capabilities: It can perform local analog
loopback and local and remote digital loopback. The operator at either end of the
line may test both modems and the line in the remote digital loopback mode.
Loopback can be controlled with either the unit’s front-panel pushbuttons or
signals passed through the DTE (PC, data-terminal) interface.

11
CHAPTER 3: Installation
3. Installation
This chapter tells you how to configure and install the Async/Sync 2-Wire Short
Haul Modem. After you finish doing this, refer to Chapter 4 for operating
information.
3.1 Placement
The Async/Sync 2-Wire Short Haul Modem is designed to be placed on a tabletop,
shelf, or bench, and is delivered completely assembled. (No provisions are made
for bolting the A/S2W SHM to any surface.)
The A/S2W SHM should be installed within 1.5 m (5 ft) of a grounded AC
outlet and must be situated within 25 ft. (7.6 m—ME376 models) or 50 ft. (15 m—
ME375 models) of the associated data terminal.
Allow at least 36" (90 cm) of clearance in front of the unit so you can access it
during operation and maintenance. Make sure that there is at least 4" (10 cm) of
clearance behind the unit for signal lines and interface cables.
3.2 Setting the Internal Controls
Before you install any cabling and definitely before you plug in the unit, you
should set the Async/Sync 2-Wire Short Haul Modem’s internal controls to suit
your application. (If you don’t feel comfortable about doing this yourself, get an
experienced technician to do it or to help you.) To access the internal controls,
first make sure the A/S2W SHM is disconnected from AC power, then unscrew the
two screws on the unit’s rear panel and slide the bottom half of the unit out from
beneath its cover.
Refer to Figure 3-1 on the next page and Table 3-1 on the succeeding pages for
the locations of the controls and their possible settings respectively.