Black Box MicroNTU G.703 AC Series 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: [email protected]
AUGUST 1998
MT240A-R2 EHN092-V35M
MT240A-48V-R2 EHN092-V35F
EHN092-530M EHN092-X21M
EHN092-530F EHN092-X21F
MicroNTU G.703 (AC)
MicroNTU G.703 (VDC)
MicroNTU G.703
Power
Network
Master
Clock
Test Mode
Loop
Loopback
Normal

1
MICRONTU G.703 (AC OR VDC)
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 la classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par le ministère des Communications du Canada.
This unit is certified.
The CE symbol on your MicroNTU G.703 indicates that it is in compliance with
the Electromagnetic Compatibility (EMC) directive and the Low Voltage Directive
(LVD) of the Union European (EU).

2
MICRONTU G.703 (AC OR VDC)
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
MICRONTU G.703 (AC OR VDC)
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
MICRONTU G.703 (AC OR VDC)
Contents
1. Specifications..............................................................................................................5
2. Introduction ...............................................................................................................6
3. Configuration.............................................................................................................7
3.1 External DIP-Switch Settings..............................................................................7
3.2 Internal Jumper Settings ..................................................................................11
4. Installation................................................................................................................16
4.1 Connection to the G.703 Network ..................................................................16
4.1.1 Twisted-Pair (120-Ohm) Connection....................................................16
4.1.2 Dual Coax BNC (75-Ohm) Connection ...............................................17
4.2 Connection to the Terminal Device................................................................17
4.3 Connection to the Power Source.....................................................................17
5. Operation .................................................................................................................18
5.1 Power-Up ...........................................................................................................18
5.2 LEDs...................................................................................................................18
5.3 Loopback Test (LAL).......................................................................................19
Appendix A. Pin Configurations................................................................................21
Appendix B. Factory Parts and Accessories ...............................................................22
B.1 Basic Standalone Units.....................................................................................22
B.2 Terminal (DTE) Interface Cables ...................................................................22
Appendix C. Safety Warnings and Requirements.....................................................23

5
MICRONTU G.703 (AC OR VDC)
1. Specifications
Network Interface G.703
Network Rate 2.048 Mbps
Network Connectors Two BNC (75-ohm) and one modular RJ-45
connector (120-ohm)
Terminal Interface EIA RS-530 (RS-422), X.21, V.35 on UD-26
using cables EHN092
Terminal Rate 2.048 Mbps (all models); 1.024 Mbps, 512 Kbps,
256 Kbps (standalone only)
Terminal Connector UD-26F
Diagnostics Loopback Test
Indicators LEDs for power, network, master clock, and
loopback test
Clocking G.703: Internal, external, network (receive
loop); DTE interface: Internal only
Power MT240A-R2: 115/230 VAC (switch-selectable),
50/60 Hz; MT240A-48V-R2: 48 VDC
Receiver Sensitivity -10 dB (0 dB = 2.4V)
Operating Temperature 32° to 140°F (0° to 60°C)
Humidity 5 to 95%, noncondensing
Altitude Up to 15,000 feet (4570 m)
Size 1.6"H x 7.3"W x 6.6"D (4.1 x 18.6 x 16.8 cm)
Weight 2 lb. (0.9 kg)

6
MICRONTU G.703 (AC OR VDC)
2. Introduction
The MicroNTU G.703 performs the tasks of three separate devices:
1. As a modem, the MicroNTU G.703 receives unstructured, synchronous
2.048-Mbps data from a G.703 network and sends it out of its DTE port
(configured as DCE).
2. As an interface converter, the MicroNTU G.703 accepts 120-ohm twisted-pair or
75-ohm dual coax connections (both types of interfaces provided). Then it
converts the signals to EIA-530 (RS-422), V.35, or X.21 format (switchable) on a
UD-26 connector.
3. As a rate adapter, the MicroNTU G.703 lets a lower-bandwidth device—
256 Kbps, 512 Kbps, or 1.024 Mbps—connect to a 2.048-Mbps G.703 link.
The MicroNTU G.703 supports internal, external, or network (receive loop)
clocking on its G.703 interface. Loopback test is built-in, and front-panel LEDs
monitor power, network, master clock, and test loop. Several power-supply options
are available:
MT240A-R2 115/230 VAC (switch-selectable)
MT240A-48V-R2 48 VDC
MT245ARackmount Card
MT246ARackmount Card
RM202, 204, 208, 216 Racks for cards 115/230 VAC (switch-selectable)

7
MICRONTU G.703 (AC OR VDC)
3. Configuration
The MicroNTU G.703 is equipped with three sets of eight DIP switches (externally
accessible), as well as seven jumpers (internal). These DIP switches and jumpers
allow configuration of clocking, data rate, test and terminal-interface options. The
MicroNTU G.703 (AC) is also equipped with an internal switch that allows
selection of 115- or 230-VAC power inputs. (This switch is not present in the
MT240A-48V-R2.)
3.1 External DIP-Switch Settings
The MicroNTU G.703’s DIP switches are located on the underside of the unit (see
Figure 3-1). Figure 3-2 shows the orientation of the switch set. The switches are
grouped into two eight-switch sets, and are externally accessible from the
underside of the MicroNTU G.703. All possible settings for the MicroNTU G.703’s
DIP switches are presented in the summary table and descriptions on the following
pages. If you have any questions about configuration, call for technical support.
Figure 3-1. DIP-switch locations.
Switch Set S2
Switch Set S1
ON
OFF

Figure 3-2. Closeup of configuration switches.
Table 3-1. Summary of DIP-switch default settings for set S1
S1 Summary Table
Position Function Factory Default
S1-1 X.21/EIA-530 Off EIA-530 or V.35*
On X.21*
S1-2 Not Used Off
S1-3 Not Used Off
S1-4 Rate Adaptation Off 2.048 Mbps
S1-5 Rate Adaptation Off
S1-6 Data Inversion Off Not Inverted
S1-7 Clock Master/Slave On Master
S1-8 Test Enable Off Front Panel
*Used with S2-1 and S2-2. See the table on page 10.
SWITCH SET S1
The configuration switches on S1 set clocking, rate adaptation, loopback enable,
data invert, and interface (see also Switch S2). The default settings are summarized
in Table 3-1.
S1-1: Terminal Interface (works in conjunction with Switch S2)
Set Switch S1-1 (as well as S2-1 and S2-2) to determine whether the signals passed
between the MicroNTU G.703 and the terminal device will follow the EIA-530
(RS-422), CCITT X.21, or CCITT V.35 standard. If S2-1 and S2-2 are set for
“EIA-530/X.21,” then the setting for S1-1 determines which of those two interfaces
is selected. Note: If S2-1 and S2-2 are set for “V.35,” switch S1-1 must be set to
“Off.” Regardless of the pinout standard chosen, the physical connector is a
female UD-26.
ON
12345678
ON
OFF
8
MICRONTU G.703 (AC OR VDC)

9
MICRONTU G.703 (AC OR VDC)
S1-1 Setting
Off EIA-530 (RS-422) interface
On X.21 interface
S1-2 and S1-3: Not Used
S1-2 and S1-3 are not used.
S1-4 and S1-5: Rate Adaptation
Set Switches S1-4 and S1-5 together to allow the MicroNTU G.703 to adapt to
terminal devices that run at data rates less than 2.048 Mbps. (The network rate
remains 2.048 Mbps regardless of the terminal-rate adaptation setting.) The setting
you select must match the data rate of your terminal device.
S1-4 S1-5 Setting
Off Off 2.048 Mbps
On Off 1.024 Mbps
Off On 512 Kbps
On On 256 Kbps
S1-6: Data Inversion
Set Switch S1-6 to determine whether or not the data stream from the local DTE is
inverted within the MicroNTU G.703 before being passed to the G.703 network.
Inverting the data stream may be necessary when the MicroNTU G.703 is being
used with an embedded G.703 device that inverts the data on the remote end.
Normally, data inversion is not necessary.
S1-6 Setting
On Data inverted
Off Data not inverted

10
MICRONTU G.703 (AC OR VDC)
S1-7: Master/Slave Clock
Set Switch S1-7 to allow the MicroNTU G.703 to provide the master clock, or
recover the clock from an external source.
S1-7 Setting
On MicroNTU G.703 is master
Off MicroNTU is slave (clock is recovered from the network)
S1-8: Loopback Test Enable
Depending upon the setting of Switch S1-8, either the MicroNTU G.703 will be
continually in loopback mode, or loopback mode will be enabled by pressing and
holding the front-panel switch. Since the front-panel switch is spring-loaded—it
returns to “Normal” operation when pressure is released—this DIP switch provides
a way of leaving the MicroNTU G.703 in “unattended” loopback mode for remote
test purposes.
S1-8 Setting
On Continual “unattended” loopback mode
Off Loopback activation by front-panel switch
SWITCH SET S2 (to be used in conjunction with S1-1)
Set DIP-Switches 2-1 and S2-2 in unison to determine the terminal interface on the
MicroNTU G.703. The alternatives are V.35 or EIA-530/X.21.
NOTE
If you select the EIA-530/X.21 scheme, you must also set Switch S1-1 to
determine whether the actual interface to be used will be EIA-530 or
X.21. Regardless of the pinout standard chosen, the physical connector
is a female UD-26. Switches S2-3 through S2-8 are reserved for future
use.
S2-1 S2-2 S1-1 Setting
On On Off V.35 Interface
Off Off Off EIA-530 Interface
Off Off On X.21 interface

11
MICRONTU G.703 (AC OR VDC)
3.2 Internal Jumper Settings
The MicroNTU G.703’s seven jumpers are located on the PC board inside the unit.
(If you have an AC model, this is also the location of the power-input switch.) To
access the jumpers:
1) Turn the power switch off.
2) Remove the power cord from the unit.
WARNING!
Always turn the power switch off and remove the power cord before
opening the unit.
3) Insert a flat-head screwdriver into an open slot on either side of the case, as
seen in Figure 3-3. Twist the screwdriver head slightly and the top half of the
case will separate from the lower half, as in Figure 3-4.
Figure 3-3. Inserting the screwdriver
in the side of the MicroNTU G.703.

12
MICRONTU G.703 (AC OR VDC)
Figure 3-4. Opening the MicroNTU G.703’s case.
4) Remove the Network Interface Module by lifting it gently upward until it
comes free from the MicroNTU G.703’s main PC board.
5) Slide out the Network Interface Module and locate the jumpers on the
bottom side of the board.
6) Configure the jumpers according to the information on the next page and
return the Network Interface Module and cover to their proper positions.

The internal jumpers mounted on the MicroNTU G.703’s PC board (labeled LK1
through LK7) are used to configure the 75- or 120-ohm network link parameters.
Figure 3-5 shows the location of the MicroNTU G.703’s jumpers on the internal PC
board.
Figure 3-5. Jumper locations.
Table 3-2 shows the factory-default jumper settings. Note that one combination of
jumper settings is required for 75-ohm operation, and another combination is
required for 120-ohm operation. The MicroNTU G.703 is factory-configured for
75-ohm operation.
Table 3-2. Summary of default jumper settings
Jumper Function 75 ohm 120 ohm Factory Default
LK1 75-Ohm TX Shield-to-GND On Off On (connect)
LK2 75-Ohm RX Shield-to-GND Opt.* Off Off (disconnect)
LK3 Reserved Off Off Off
LK4 120-Ohm Shield-to-GND Off Opt.* Off (disconnect)
LK5 Configuration Auto-Sense On Opt.* On (enabled)
LK6 75-Ohm Input Impedance On Off
LK7 75-Ohm Input Impedance On Off
*Opt.= optional setting. All others are required for proper operation.
LK 2
LK 4
LK 1
LK 3
LK 5
LK 7
LK 6
13
MICRONTU G.703 (AC OR VDC)
}On (75 ohm)

14
MICRONTU G.703 (AC OR VDC)
Listed below are each jumper’s function and possible settings. When configuring
the jumpers, take care not to lose the individual straps.
LK1: 75-Ohm Transmit Shield-to-Ground Connection
This setting determines whether the shield of the 75-ohm (coax) transmit cable is
connected to earth ground. This connection must be made when operating in 75-
ohm (unbalanced) mode. Conversely, this connection must not be made when
operating in 120-ohm (balanced) mode.
LK1 Setting
Strap On 75-ohm TX Shield-to-GND Connection Made
Strap Off 75-ohm TX Shield-to-GND Connection Broken
LK2: 75-Ohm Receive Shield-to-Ground Connection
This setting determines whether the shield of the 75-ohm (coax) receive cable is
connected to earth ground. This connection is optional when operating in 75-ohm
(unbalanced) mode. This connection must not be made when operating in 120-
ohm (balanced) mode.
LK2 Setting
Strap On 75-ohm RX Shield-to-GND Connection Made
Strap Off 75-ohm RX Shield-to-GND Connection Broken
LK3: Reserved for future use
This strap is reserved for future use and must remain off.
LK3 Setting
Strap On Not a valid setting
Strap Off Normal operation
LK4: 120-Ohm Shield-to-Ground Connection
This setting determines whether the shield of the 120-ohm (modular) cable is
connected to earth ground. This connection is optional when operating in 120-
ohm (balanced) mode. This connection must not be made when operating in 75-
ohm (unbalanced) mode.

15
MICRONTU G.703 (AC OR VDC)
LK4 Setting
Strap On 120-ohm RX Shield-to-GND Connection Made
Strap Off 120-ohm RX Shield-to-GND Connection Broken
LK5: Configuration Auto-Sense
This setting determines whether the host can automatically sense the configuration
of the MicroNTU. The operation of the MicroNTU is not affected by this jumper
setting. Auto-sense should be enabled when operating in 75-ohm (unbalanced)
mode. Current interface standards do not list this feature for 120-ohm (balanced)
mode.
LK5 Setting
Strap On Auto-sense enabled
Strap Off Auto-sense disabled
LK6 and LK7: 75-Ohm Termination Impedance
These jumpers set the termination impedance correctly for 75-ohm operation.
Both jumpers must be in place when operating in 75-ohm (unbalanced) mode.
Conversely, both jumpers must be removed when operating in 120-ohm
(balanced) mode.
LK6 LK7 Setting
On On 75-ohm operation
Off Off 120-ohm operation

16
MICRONTU G.703 (AC OR VDC)
4. Installation
Once the MicroNTU G.703 is properly configured, it is ready to connect to your
system. This section tells you how to connect the MicroNTU G.703 to the G.703
network and terminal-device interfaces.
4.1 Connection to the G.703 Network
The MicroNTU G.703 supports 2.048-Mbps communication over an unstructured
G.703 network. Both 120-ohm twisted-pair and 75-ohm coax interfaces are
provided on the MicroNTU G.703’s rear panel (see Figure 4-1). Be sure the unit is
configured properly to operate in either 120- or 75-ohm mode, and that the
network connection is grounded appropriately (see Chapter 3).
Figure 4-1. MicroNTU G.703 (AC) rear panel.
4.1.1 T WISTED -P AIR (120-O HM ) C ONNECTION
The MicroNTU G.703 is equipped with a single RJ-45 jack for connection
to a 120-ohm (modular) twisted-pair G.703 network interface. The pinout
of this jack is as follows:
RJ-45 Pins Signal
1 and 2.........................Receive pair (from network)
3...................................Shield reference point
4 and 5.........................Transmit pair (to network)
6...................................Shield reference point
7...................................Not used
8...................................Not used
Network
DTE Interface
ON 1
OFF 0
MicroNTU G.703 (VDC) has a terminal strip

17
MICRONTU G.703 (AC OR VDC)
4.1.2 D UAL C OAX BNC (75-O HM ) C ONNECTION
In addition to the 120-ohm twisted-pair connection, the MicroNTU G.703 is
equipped with dual female BNCs (TX and RX) for connection to a 75-ohm dual
coax G.703 network interface. The outer conductor of the coax cable is isolated
from system earth ground.
4.2 Connection to the Terminal Device
The MicroNTU G.703 is wired as a DCE, and—when configured properly—
supports communication with a variety of terminal (DTE) devices. Compatible
interface standards include EIA-530 (RS-422), CCITT X.21, and CCITT V.35.
All interfaces are supported on a female UD-26 connector (a subminiature 26-pin
“D” connector designated the “alt A” in the EIA-232 Standard). The various
physical/electrical connections mentioned above are achieved by changing the
MicroNTU G.703’s DIP-switch settings and attaching different adapter cables.
If you want to construct your own terminal-adapter cable, consult the pinout
diagrams in Appendix A. If you want to purchase a terminal-adapter cable
specifically designed to work with the MicroNTU G.703, refer to Appendix B.
4.3 Connection to the Power Source
As described in Section 3.3, the MicroNTU G.703 is available with two power-
supply options. The AC power-supply option (MT240A-R2) uses a female IEC
power-cord interface, for which you can use various domestic and international
power cords. (Refer to Appendix B.) The DC power-supply option (MT240A-48V-
R2) operates in 48-VDC environments and is equipped with a 3-pin terminal-strip
style DC power cord.

18
MICRONTU G.703 (AC OR VDC)
5. Operation
Once the MicroNTU G.703 is configured and installed, it should operate
transparently.
5.1 Power-Up
To apply power to the MicroNTU G.703, first be sure that you have read Section
3.3, and that the unit has the proper voltage setting and fuse. The wrong setting or
fuse could result in damage to the unit and connected equipment, and may
constitute a fire hazard. Having checked the voltage setting, plug the AC power
cord into both the MicroNTU G.703 and the AC outlet. Then power up the unit
using the rear Power switch.
NOTE
The PWR LED should glow when power is applied to the unit.
Figure 5-1. The front panel.
5.2 LEDs
The MicroNTU G.703 features four front-panel LEDs that indicate the status of
power, network connection, master clock, and loopback test. Figure 5-1 shows the
location of each LED. Following Figure 5-1 is a description of each LED’s function.
Loop
Test Mode
Loop Back
Normal
Master Clock
Power
Network

19
MICRONTU G.703 (AC OR VDC)
Power Glows red when the MicroNTU G.703 is powered up.
Network Glows green when the MicroNTU G.703 is receiving
correctly encoded data from the line-interface equipment.
Master Clock Glows green when the MicroNTU G.703 is configured as
the master-clock unit.
Loop Glows green when the MicroNTU G.703 is in loopback
mode.
5.3 Loopback Test (LAL)
The MicroNTU G.703 is equipped with a Local Analog Loopback (LAL) mode to
assist in evaluating the operation of the local MicroNTU G.703. Any data sent to
the local MicroNTU G.703 in this test mode will be echoed back (returned) to the
user device. For example, characters typed on the keyboard of a terminal will
appear on the terminal screen. To perform an LAL test:
a.) Activate LAL by moving the front-panel toggle switch up and holding it in
the “Loopback” mode. The “Loop” LED should glow. Once LAL is
activated, the MicroNTU G.703 transmit output is connected to its own
receiver.
NOTE
The front-panel switch is spring-loaded, so it will return to “Normal”
operating mode when pressure is released. To put the MicroNTU G.703
in continual loopback mode, for the purpose of performing a BER test,
move DIP switch S1-8 to the “ON” position (see Section 3.1).
b.) Verify that the data-terminal equipment is operating properly and can be
used for a test. If a fault is indicated, call your supplier for technical support
or replace the unit.
c.) Perform a BER (bit error rate) test on each unit. If the BER test equipment
indicates no faults, but the data terminal indicates a fault, follow the
manufacturer’s checkout procedures for the data terminal. Also, check
th interface cable between the terminal and the MicroNTU G.703.