Black Box Local Mux-6 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]
MARCH 1997
MX515A
MX515AE
Local Mux-6
Local Mux-6
POWER
RLB
LLB
TEST LOCAL REMOTE
SYNC LOSS

3
LOCAL MUX-6
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.

4
LOCAL MUX-6
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.

5
LOCAL MUX-6
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.

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LOCAL MUX-6
TRADEMARKS
All applied-for and registered trademarks are the property of their respective
owners.

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LOCAL MUX-6
Contents
1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.1 Sub-Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.2 Main Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.3 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.1 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3 Installation in 19" Racks . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.3.2 Installation of Unit . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.4 Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.4.1 AC Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.4.2 Sub-Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.4.3 Main Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
4. Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.2 Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.3 Operating Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.4 System Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
4.5 Fault Isolation annd Troubleshooting . . . . . . . . . . . . . . . .25

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LOCAL MUX-6
1. Specifications
1.1 Sub-Channels
Transmission Format—Asynchronous
Data Rate—Up to 19.2 kbps (refer to Table 2-1)
Distortion—Refer to Table 2-1
Interface—EIA RS-232-C/CCITT V.24
Connectors—(6) DB25 female
Number of Sub-channels—Up to twelve by attaching a channel doubler
to each of the connectors
Mode of Operation—Full duplex
1.2 Main Channel
Electrical Interface
Transmission Line—4-wire unconditioned telephone lines (two twisted pairs)
Operating Range—Maximum of 1.6 km (1 mile) on 22 AWG cable
Data Rate—1.2288 Mbps
Output Format—Balanced, transformer-isolated 6 Vp-p (on 100 Ω)
Input Resistance—100 Ω
Connector—Terminal block

9
LOCAL MUX-6
1.3 General
Diagnostics
Local digital loopback—Activated by pushbutton.
Remote digital loopback—Activated by pushbutton.
Switches/Indicators
Power Indicator (Green)—On when unit is powered.
Test Indicator (Yellow)—On when local or remote unit is performing
a loopback.
Local Sync Loss Indicator (Red)—On when synchronization is lost at local
unit.
Remote Sync Loss Indicator (Red)—On when synchronization is lost at
remote unit.
LLB Switch—When pressed, unit is performing local loopback.
RLB Switch—When pressed, unit is performing remote loopback.
Physical Description
Size—1.72"H (1U) x 13.3"W x 8.6"D (4.4 x 33.8 x 22 cm)
Weight—3.5 lb. (1.6 kg)
Environment
Temperature—32 to 122°F (0 to 50°C)
Humidity—Up to 90% non-condensing.
Power
Power Requirements—MX515A: 115 VAC, 60 Hz; MX515AE: 230 VAC, 50 Hz

10
LOCAL MUX-6
2. Introduction
2.1 General
The Local Mux-6 is a full-duplex time-division asynchronous multiplexor
enabling up to twelve async terminals to be multiplexed onto a single
channel. The Local Mux-6 is intended for use in manufacturing facilities,
building complexes, campuses, and other similar point-to-point applications.
2.2 Functional Description
The Local Mux-6 contains six sub-channels that can be expanded to twelve
through connection of channel-doubler cables. The number of channels
available (6/12) is set by a user-selectable strap.
When the unit is set for six channels, each channel can be used to transmit
full-duplex data end to end. When the unit is set for twelve channels, each
sub-channel can be used for either data or control-signal transmission,
according to the specific application. For example, six channels can be used
to transmit full-duplex data and six can be used to transmit control signals
end to end, or else the full twelve channels can be used to transmit full
duplex data end to end.
The Local Mux-6 comes with a 4-wire terminal block for transmission over
two twisted pairs.
Multiplexing is implemented using an over-sampling technique.
Each of the twelve channels is sampled at 78.6 kbps. Table 2-1
summarizes Local Mux-6 performance.
NOTE
Whenever possible (if the number of channels is less than or equal to 6),
we recommend that you operate the Local Mux-6 in the six-channel
mode, which results in less distortion.

11
LOCAL MUX-6
Table 2-1. Performance in Various Modes of Operation.
No. of Max Electrical Distortion (%)
Sub-channels Data Rate
in use (Kbps)
6 19.2 12.5
6 38.4 —
12 19.2 25.0
2.3 Applications
The Local Mux-6 is used mainly for point-to-point configurations where
distances of up to several kilometers are involved. A typical application is
demonstrated in Figure 2-1, where a cluster of terminals is connected to a
host computer through a single link. Different configurations are available
using the 4-wire transmission media. The maximum data rate in a point-to-
point configuration is 19.2 kbps for 12 data subchannels, 6 data subchannels,
or 6 data and 6 control subchannels.

12
LOCAL MUX-6
Figure 2-1. Typical Point-to-Point Installation.
For installations involving clusters of terminals distributed in several
locations, Local Mux-6 units may be installed in a ring-type configuration
(refer to Figure 2-2). At each site the unconnected channels must be
bypassed by shorting Pins 2 and 3 of the relevant sub-channel connector.
Local Mux-6 Local Mux-6
Async
Computer

13
LOCAL MUX-6
Table 2-2. Distortion.
Data Rate Distortion Number of
on Each per Node Nodes/Sites
Sub-Channel (%)
19.2 kbps 25.00 2
9.6 kbps 12.50 3
4.8 kbps 6.250 4
2.4 kbps 3.125 8
1.2 kbps 1.5625 16
Figure 2-2. Typical Ring Installation.
4
TERM
4
TERM
4
TERM T
R
9
12
5
8
1
4
T
R
R
T
R
T
1
12
HOST
2WIRE 2WIRE
2WIRE
2WIRE

14
LOCAL MUX-6
3. Installation
3.1 Site Preparation
The Local Mux-6 must be installed within 5 feet (1.5 m) of a grounded AC
outlet.
3.2 Setup
1. Unscrew the two upper cover screws located at the back of the unit
(refer to Figure 3-3).
2. Slide the rear drawer out.
3. Locate the strap marked “select 6 or 12 channels” (indicated by an arrow
on the circuit board). For up to 6 channels with no control applications,
place the strap between the center pin, and the one marked “6.” For any
other applications, place the strap between the center pin and the one
marked “12” (refer to Figure 3-1).
4. Locate the strap marked GND. According to your requirements, set the
signal ground to be connected to shielding (chassis) ground or floating
(NC).
5. Replace the rear drawer.
6. Fasten the two upper cover screws at the back of the unit.
Figure 3-1. Strapping Diagram.
12
6
SELECT
6 OR 12
CHANNELS
GND
NC

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LOCAL MUX-6
3.3 Installation in 19” Racks
3.3.1 G ENERAL
The Local Mux-6 can be installed in a 19" rack. Its height is slightly less than
1U (1.75"), and the width is slightly less than the available mounting width.
WARNING
Disconnect the units from mains power while performing the following
procedures. If you don’t, you could be shocked!
3.3.2 I NSTALLATION OF A U NIT
The rack adapter components for single-unit installation include two short
brackets. The brackets are fastened by means of screws to the side walls for
the case, as shown in Figure 3-2. The brackets are attached to the two side
walls of the unit.
1. To prepare the unit for rack installation, attach the two brackets to the
side walls of the unit. Each bracket is fastened by means of two screws
(with flatwashers), which are inserted into the two front holes on the
wide wall (nuts are already in place, on the inner side of the wall).
2. After attaching the brackets, the unit is ready for installation in the
19” rack. Fasten the brackets to the side rails of the 19" rack by means
of four screws—two per side.

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LOCAL MUX-6
Figure 3-2. Installation of a Unit in a 19" Rack.
3.4 Electrical Installation
In the following discussions, refer to Figure 3-3 (rear panel).
3.4.1 AC P OWER
AC power is supplied to the Local Mux-6 through a 5 feet (1.5 m) cord
terminated by a grounded 3-wire plug. The AC cord is fused at the rear
panel AC power receptacle of the unit. A slow-blow fuse of 0.1A is required
for 230V operation, and a 0.2A fuse is required for 115V operation.
3.4.2 S UB - CHANNELS
Six D-type 25-pin female connectors on the rear panel enable connection to
the unit. Detailed information about the signals present at these connectors
is given in Table 3-1. For twelve-channel operation, channel doublers (CD)
are required. Refer to Figure 3-4 for the pinout of the CD. For six-channel
operation, with full duplex data and end-to-end control signals on each
channel, refer to Figure 3-5 (DTR to DSR control signal) or to Figure 3-6
(RTS to DCD control signal).

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LOCAL MUX-6
3.4.3 M AIN C HANNEL
A 5-screw terminal block is located at the rear panel, marked TX-A, TX-B,
CHASSIS GND, RX-A, RX-B for connecting transmit and receive wires and
the cable shield (if available). TX connectors at the local unit must be
connected to RX connectors at the opposite unit.
Figure 3-3. Rear Panel.
CH 1/7 CH 2/8 CH 3/9
CH 4/10 CH 5/11 CH 6/12
MAIN CHANNEL
FUSE
~115V/O.2AS.B.
RX-B TX-BRX-A TX-A
m

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LOCAL MUX-6
Table 3-1. Sub-Channel Connector Pin Assignment.
CCITT EIA Pin Signal Name Description
V.24 RS-232C No.
101 AA 1 Protective Ground Chassis ground. May be
isolated from signal
ground.
102 AB 7 Signal Ground Common signal and DC
power-supply ground.
103 BA 2 (14) Transmit Data Serial digital data from a
terminal or other source
into the Local Mux-6.
104 BB 3 (16) Receive Data Serial digital data output
from the Local Mux-6.
105 CA 4 (19) Request to Send A positive level to the
Local Mux-6 when data
transmission is desired.
106 CB 5 (13) Clear to Send A positive level from the
Local Mux-6 (if data
transmission is possible).
107 CC 6 (21) Data Set Ready A positive DC voltage
(+8V) from the Local
Mux-6 indicating the unit
is powered.
109 CF 8 (12) Receive Line A positive level from the
Signal Detector Local Mux-6 except when
(Carrier Detect) either a sync loss occurs
or remote loopback is
performed.
—— 9 +8 volts These signals are
10 -8 volts reserved for data-set
testing and for powering
miniature modems.
NOTE: Pin numbers in parentheses are for the secondary channel
available when using a channel-doubler cable.

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LOCAL MUX-6
Figure 3-4. Connecting Channel Doubler to Local Mux-6 Sub-Channel.
1
2
3
4
5
6
8
15
17
20
24
7
14
16
19
13
21
12
11
18
25
23
1
2
3
4
5
6
8
15
17
20
24
7
14
16
19
13
21
12
11
18
25
23
1
2
3
4
5
6
8
15
17
20
24
7
1
2
3
4
5
6
8
15
17
20
24
7
Local Mux-6
Sub-Channel
Connector
Channel Doubler
Port A
Port B
Not used
Signal Ground
Not used
Protective Ground
Transmitted Data (TD)
Received Data (RD)
Request to Send (RTS)
Clear to Send (CTS)
Data Set Ready (DSR)
Received Line Signal Detector
Secondary TD
Secondary RD
Secondary RTS
Secondary CTS
Secondary DSR
Secondary RLSD

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LOCAL MUX-6
Figure 3-5. DTR to DSR End-to-End Control Signal.
Figure 3-6. RTS to DCD End-to-End Control Signal.
1
2
3
4
5
6
8
7
14
16
1
2
3
4
5
6
7
8
1
2
3
4
5
6
8
7
14
16
1
2
3
4
5
6
8
7
14
16
1
2
3
4
5
6
8
20
7
1
2
3
4
5
6
8
7
14
16
Local Mux-6
Sub-Channel
Connector Channel Doubler
Special
Cable 1
Protective Ground
Transmitted Data (TD)
Received Data (RD)
Request to Send (RTS)
Clear to Send (CTS)
Data Set Ready (DSR)
Received Line Signal Detector
Signal Ground
Secondary TD
Secondary RD
Local Mux-6
Sub-Channel
Connector Channel Doubler
Special
Cable 2
Protective Ground
Transmitted Data (TD)
Received Data (RD)
Request to Send (RTS)
Clear to Send (CTS)
Data Set Ready (DSR)
Received Line Signal Detector
Signal Ground
Secondary TD
Secondary RD

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LOCAL MUX-6
4. Operating Instructions
4.1 General
This chapter covers:
• A list of controls and indicators together with their functions.
• An operating procedure covering turning on the power,
operating instructions, and turning off the power.
• Information on strapping.
• A unit system test procedure for use by the operator and technician.
Installation procedures given in Chapter 3 must be completed and
checked before operating the Local Mux-6.
4.2 Controls and Indicators
Tables 4-1 and 4-2 list the function of the Local Mux-6 indicators
and switches. The Local Mux-6 front panel is shown in Figure 4-1.
Figure 4-1. Local Mux-6 Front Panel.