MAY 2001
MT255A-M
MT256A-F
MT257A
G.703 Adapters and
Balun Mate II
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 724-746-0746
Mailing address: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: info@blackbox.com
1
FCC/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, might 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 Industry Canada.
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 Industrie Canada.
2
G.703 ADAPTERS AND BALUN MATE II
EUROPEAN UNION DECLARATION OF CONFORMITY
The manufacturer declares that this equipment complies with the
requirements of the EMC Directive 89/336/EEC, as well as the Low Voltage
Directive (LVD).
3
NOM STATEMENT
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.
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G.703 ADAPTERS AND BALUN MATE II
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.
5
TABLE OF CONTENTS
Contents
Chapter Page
1. Specifications .............................................................. 6
2. Introduction ............................................................... 8
3. Configuration ........................................................... 12
4. Installation and Operation ...................................... 15
5. Troubleshooting ....................................................... 17
5.1 Calling Black Box .............................................. 17
5.2 Shipping and Packaging ................................... 18
Appendix: Block Diagram .............................................. 19
6
G.703 ADAPTERS AND BALUN MATE II
1. Specifications
Compliance: CE, FCC Part 15 Subpart J Class A, IC Class/
classe A
Interfaces: ITU CTR-12 G.703 (unstructured):
Coaxial: Unbalanced 75-ohm (RG-59 or 2002 cable);
Twisted-pair: Balanced 120-ohm (shielded or unshielded
cable)
Data Rate: Up to 2.048 Mbps (E1)
User Controls: Internal jumpers for shield connection or
disconnection:
MT255A-M, MT256A-F: (2);
MT257A: (2) for each of the (16) port-card modules
Indicators: None
Connectors:
Coaxial: Dual 1.6/5.6-mm:
MT255A-M: (1) Male (on 6" [15.2 cm] cable pigtails);
MT256A-F: (1) Female;
MT257A: (16) Female (one on each module);
Twisted-pair: Shielded RJ-45 female:
MT255A-M, MT256A-F: (1);
MT257A: (16), one on each module
7
CHAPTER 1: Specifications
Isolation: 500 volts AC/DC between coax and twisted-pair
sides
Temperature Tolerance: 32 to 122˚F (0 to 50˚C)
Humidity Tolerance: 5 to 95% noncondensing
Power: From interfaces
Size:
MT255A-M (excluding cable pigtails), MT256A-F:
2.7"H x 1.7"W x 0.8"D (6.9 x 4.3 x 2 cm);
MT257A:
Rack chassis: 3.5"H x 19"W x 1.9"D
(8.9 x 48.3 x 4.8 cm);
Individual port-card modules: 3.4"H x 1"W x 1.75"D
(8.6 x 2.5 x 4.4 cm)
Weight:
MT255A-M: 2.7 oz. (77 g);
MT256A-F: 1.4 oz. (41 g);
MT257A:
Rack chassis: 2.6 lb. (1.2 kg);
Individual port-card modules: 0.4 oz. (10 g)
8
G.703 ADAPTERS AND BALUN MATE II
2. Introduction
The G.703 Adapters and the Balun Mate II enable
75-ohm coaxial G.703 equipment/networks to
communicate with 120-ohm twisted-pair G.703
equipment/networks. They’re specifically designed to
address the Open Network Provision (ONP)
requirement that European PTTs offer 120-ohm twistedpair terminations to their customers. Some PTTs and
private carriers had standardized on 75-ohm coax, or
have customers whose CPE has only 75-ohm
connections. The Adapters and the Balun Mate II help
solve this termination mismatch by converting 75-ohm
signals to 120-ohm signals and vice versa, at data rates up
to full E1 speed (2.048 Mbps).
The MT255A-M model of the G.703 Adapter has a
pair of 6" (15.2-cm) coaxial pigtails with male
connectors that can plug into the female coaxial
connectors of an existing device or termination.
The MT256A-F model of the G.703 Adapter has a pair
of female coaxial connectors that existing coaxial cables
can be plugged into.
9
CHAPTER 2: Introduction
The Balun Mate II (MT257A) is designed to be
mounted in a 19" rack. It contains sixteen individual
port-card modules, each of which has a pair of female
coaxial connectors for existing cables.
The coaxial connectors on all of these models are the
1.6/5.6-mm types used extensively in telephone sites.
On the twisted-pair side, each G.703 Adapter and each
of the Balun Mate II’s port-card modules has a standard
RJ-45 jack.
Here’s a summary of the main features of the
Adapters and the Balun Mate II:
• Connect 75-ohm dual-coax G.703 terminations to
120-ohm twisted-pair G.703 terminations.
• Bidirectional signal conversion.
• Uses 1.6/5.6-mm coaxial connectors and standard
RJ-45 twisted-pair connectors, all of which have low
insertion loss.
• Data rates up to 2.048 Mbps.
10
G.703 ADAPTERS AND BALUN MATE II
• Interface-powered—no AC or battery power
required.
• Adapters are housed in low-profile, flameretardant enclosures with either male or female
coaxial connectors.
• Balun Mate II can be mounted in 2U of vertical
space in a 19" rack and can patch as many as
sixteen terminations.
Figures 2-1 and 2-2 on the next page show typical G.703
Adapter applications. The Balun Mate II will also be
used for these kinds of applications.
For a block diagram of the circuitry of the Adapters
and the Balun Mate II’s port-card modules, see the
Appendix.
11
CHAPTER 2: Introduction
Figure 2-1. Using a single Adapter to connect a coaxial G.703 device to
a twisted-pair G.703 device.
Figure 2-2. Using a pair of Adapters to run a G.703 link through
twisted-pair site wiring.
Adapter
Adapter
Adapter
Telco Distribution
Frame (PBX, Mux, etc.)
with Coax G.703 Ports
Telco Distribution
Frame (PBX, Mux, etc.)
with Coax G.703 Ports
Transmission Equipment
(CSU/DSU, NTU, FRAD, etc.)
with Twisted-Pair
G.703 Ports
Transmission Equipment
(CSU/DSU, NTU, FRAD, etc.)
with Coax G.703 Ports
Site Wiring
(UTP)
Twisted-Pair
Cabling
Wide-Area
Network
Wide-Area
Network
12
G.703 ADAPTERS AND BALUN MATE II
3. Configuration
The G.703 Adapters and the Balun Mate II have only
one user-settable configuration option. They express
Transmit Data (TX) shield to the twisted-pair cabling on
RJ-45 Pin 3 and Receive Data (RX) Shield on RJ-45
Pin 6. Pin 3 is always connected to the shield on the
RJ-45 connector itself, but in the factory-default settings
of the Adapters and the Balun Mate II, it’s also
connected to the shield of the coaxial TX cable, and
RJ-45 Pin 6 is connected to the shield on the coaxial RX
cable.
This should be acceptable in most cases; if it is,
proceed with Chapter 4. But sometimes it’s better for
the twisted-pair and coaxial shields to be isolated from
each other. For example, in order to avoid electrical
“ground loop” problems, the two shields should be
isolated on one of any pair of Adapters or modules
connected back-to-back. So you might want to change
this setting, which involves removing jumpers.
Both of the Adapter models have a pair of internal
jumpers labeled JP1 and JP2, while the Balun Mate II
has a pair of these jumpers mounted on each of its
sixteen port-card modules. In their factory-default
13
CHAPTER 3: Configuration
installed settings, JP1 links RJ-45 Pin 3 to the coax TX
shield, while JP2 links RJ-45 Pin 6 to the coax RX shield.
To remove these jumpers in order to break these
links, you’ll need to open the case of your Adapter or
temporarily remove each port-card module from your
Balun Mate II. Follow these steps, taking all reasonable
precautions against static electricity:
1. Make sure that the Adapter or module is
disconnected from all cables and from all other
devices.
2A. If you’re setting the jumpers on an Adapter, insert a flat-
blade screwdriver into the slot on the side of the
Adapter’s case and twist. The case will pop open,
exposing the circuit board.
2B. If you’re setting the jumpers on a Balun Mate II module,
unscrew the nuts and washers on the module from
the two screwposts embedded in the chassis’ front
panel. (You might need a nutdriver to do this.)
Once this is done, carefully slide the module out
of the back of the rack chassis.
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G.703 ADAPTERS AND BALUN MATE II
3. Looking down at the top of the circuit board with
the RJ-45 jack facing to the left, you should be able
to see both jumpers in the middle of the board:
JP1 toward the back and JP2 toward the front.
Move either or both of these jumpers so that they
are sitting on just one jumper post instead of
connecting both posts. The shield link that passes
through each jumper you move will be broken.
4A. If you’ve set the jumpers on an Adapter, realign the
case halves with the end inserts and snap the case
halves back together.
4B. If you’ve set the jumpers on a Balun Mate II module,
carefully slide the module back into its slot in the
rack chassis, guiding its coaxial connectors
through their holes in the chassis’ front panel.
Then screw the module’s nuts and washers back
into the screwposts on the back of the front panel
to reattach the module to the chassis.
15
CHAPTER 4: Installation and Operation
4. Installation and Operation
To connect a G.703 Adapter or Balun Mate II to your
G.703 devices and/or networks, take these steps:
1. If you are using an MT255A-M Adapter, connect
its coaxial pigtails to your device’s coaxial G.703
ports. If you are using an MT256A-F Adapter or
Balun Mate II, connect your coaxial G.703 cables
to its coaxial ports. Make sure to connect TX to
TX and RX to RX. If the cables or device ports you
want to attach have regular BNC connectors
rather than 1.6/5.6-mm connectors, you’ll need to
use BNC-to-1.5/6.5-mm adapters or adapter cables
(call Black Box Technical Support).
2. Connect your G.703 twisted-pair cabling to the
Adapter’s or Balun Mate II’s RJ-45 jack(s). The
plug of each cable you’ll attach to these jacks
should be pinned to match them:
Pin 1: Transmit Data + (TX+)
Pin 2: Transmit Data – (TX–)
Pin 3: Transmit Data (TX) shield
Pin 4: Receive Data + (RX+)
Pin 5: Receive Data – (RX–)
Pin 6: Receive Data (RX) shield
Pins 7 and 8: No connection
81
RJ-45 jack
(female)
16
G.703 ADAPTERS AND BALUN MATE II
As soon as you connect the Adapter or Balun Mate II to
a working G.703 device/network on both the coaxial
and twisted-pair sides, it will begin operating
immediately, drawing power from the interfaces and
translating between them. It has no ON/OFF switch.
17
CHAPTER 5: Troubleshooting
5. Troubleshooting
5.1 Calling Black Box
If your G.703 Adapter or Balun Mate II seems to be
malfunctioning, do not attempt to alter or repair it. It
contains no user-serviceable parts. Call Black Box
Technical Support at 724-746-5500; the problem might
be solvable over the phone.
Before you call, 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;
and
• the results of any testing you might have already
done.
18
G.703 ADAPTERS AND BALUN MATE II
5.2 Shipping and Packaging
If you need to transport or ship your G.703 Adapter or
Balun Mate II:
• Package it carefully. We recommend that you use
the original container.
• If the shipping is return- or repair-related, include
everything you received with the Adapter or Balun
Mate II when you pack it. Contact Black Box to get
a Return Authorization (RA) number.
19
APPENDIX: Block Diagram
Appendix: Block Diagram
Although the arrows in this diagram showing data flow
are bidirectional, and the Adapters and Balun Mate II do
support bidirectional data transfer, the direction of flow
on the transmit lines (coax TX, twisted-pair pins 1 and 2)
will always be opposite to the direction of flow on the
receive lines (coax RX, twisted-pair pins 4 and 5). Which
signal is input and which is output on either interface
will usually depend on the DTE/DCE configuration of
the attached devices.
JP1
JP2
Coax Transmit Shield
Coax
Twisted
Pair
Transmit
Shield on
RJ-45 Pin 3
Receive Shield on
RJ-45 Pin 6
Signal
Conversion
Shield on
RJ-45
Jack
Coax Receive Shield
Receive (RX)
Transmit (TX)
Transmit (TX)
Receive (RX)
NOTES
1000 Park Drive • Lawrence, PA 15055-1018 • 724-746-5500 • Fax 724-746-0746
© Copyright 2001. Black Box Corporation. All rights reserved.
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