Black Box IC520A-F User manual

APRIL 1999
IC520A-F
IC520A-M
IC521A-F
IC521A-M
Async RS-232 to 2-Wire
RS-485 Converter
CUSTOMER SUPPORT INFORMATION
Order toll-free in the U.S. 24 hours, 7 A.M. Monday to midnight Friday: 877-877-BBOX
FREE technical support, 24 hours a day, 7 days a week: Call 724-746-5500 or fax [phone]
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [email protected]

1
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
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 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.
The CE symbol on your equipment indicates that it complies with the
Electromagnetic Compatibility (EMC) directive and the Low Voltage
Directive (LVD) of the Union European (EU).

2
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
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.

3
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
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.

4
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
TRADEMARKS
The trademarks mentioned in this manual are the sole property
of their owners.

5
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
CONTENTS
1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Connecting the EIA-232 Interface . . . . . . . . . . . 11
4.2 Connection to the RS-485 Interface . . . . . . . . . . 12
4.2.1 Connecting via the RJ-45 Connector . . . . . 12
4.2.2 Connecting via the Terminal Block . . . . . . 14
5. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendix: RS-232 Pin Configuration
and DCE Connection Wiring . . . . . . . . . . . . . . . . . . 20

6
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
1. Specificatons
Transmission Format — Asynchronous
Data Rate — Up to 115,200 bps
Distance — Up to 4000 feet (1219.2 m)
on Category 5 solid cable
Connectors — IC520A-F: (1) DB25 female,
(1) 4-screw terminal block; IC520A-M: (1) DB25
male, (1) 4-screw terminal block;
IC521A-F: (1) DB25 female, (1) RJ-45 female;
IC521A-M: (1) DB25 male, (1) RJ-45 female
Interface — RS-232 is DCE
Transmit Line — 2-wire unconditioned twisted pair
(24 AWG, solid, unshielded twisted pair [CAT-5])
Transmit Mode — 2-wire half-duplex
Surge Protection — 600 W power dissipation at 1 ms
Temperature — 32 to 122 °F (0 to 50 °C)
Humidity — 5 to 95%, noncondensing

7
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
Power — Draws operating power from RS-232 data
and control signals; no AC power or batteries
required
Size — 0.7"H x 2.1"W x 2.7"D (1.7 x 5.3 x 6.9 cm)
Weight — 0.1 lb. (0.06 kg)

8
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
2. Introduction
2.1 Description
The Async RS-232 to 2-Wire RS-485 Converter provides
excellent versatility in a compact package. Requiring
no AC power or batteries for operation, the Converter
supports asynchronous RS-232 data rates to 115.2 kbps
over one unconditioned twisted pair in half-duplex
mode. The line is automatically turned around from
receiving to transmitting upon the beginning of
receiving of RS-232 data. No RS-232 control signal is
needed to turn around the line.
The Converter is equipped with either male or female
DB25 connectors for RS-232. For the twisted pair
connection, you can choose either a 4-wire terminal
block or an RJ-45 female connector. Silicon Avalanche
Diodes provide 600 watts per wire of protection against
harmful data-line transient surges.

9
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
2.2 Features
• Operates asynchronously, half-duplex,
point-to-point over two wires
• Data rates to 115.2 kbps
• No AC power or batteries are required
• Compact size
• Twisted-pair connection via screw terminals
or RJ-45
• Silicon Avalance Diode surge protection

10
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
3. Configuration
The Converter requires no configuration. It’s factory-
configured as Data Communication Equipment (DCE).
It connects to Data Terminal Equipment (DTE) via its
DB25 RS-232 port. Figure 3-1 shows the RS-232 DB25
connector and terminal blocks on the printed circuit
board.
Figure 3-1. Top View of the Converter’s Circuit Board.
+RCV- G -XMT+

11
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
4. Installation
This section tells you how to properly connect the
Converter to the RS-485 and RS-232 interfaces, and
how to operate the Converter.
4.1 Connecting the EIA-232 Interface
The EIA-232 interface is factory-configured as DCE. It
connects directly to DTE such as a terminal or PC. If you
must use a cable to connect to the DTE and your DTE
device uses a DB25 connector, use a straight-through
cable no longer than 50 feet (15.2 m).
If your DTE equipment uses a DB9 connector,
use one of the two following Black Box DB9 to DB25
adapters: FA520A-R2 (DB9 female to DB25 male) or
FA521A (DB9 male to DB25 female).
For your convenience, the Converter comes with
either a male or female DB25 connector on the
RS-232 side.

12
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
4.2 Connection to the RS-485 Interface
To function properly, the Converter must have one
twisted pair of metallic wire. This pair must be “dry”
(unconditioned) metallic wire, solid conductor,
unshielded twisted pair, between 19 and 26 AWG (the
higher-numbered gauges may limit distance somewhat).
We recommend using Category 5 solid 24 AWG cable.
For your convenience, the Converter comes with
either an RJ-45 connector or a terminal block on the
RS-485 side.
4.2.1 C ONNECTING VIA THE RJ-45 I NTERFACE
The RJ-45 versions of the Converter use an RJ-45
connector on the RS-485 side. This connector is
prewired for a standard telco wiring environment.
The signal/pin relationships are shown in Figure 4-1.

13
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
Figure 4-1. RJ-45 Interface for the Twisted Pair Line.
Figure 4-2. Orientation of the RJ Connector.
1
1
1
2
3
4
5
6
7
8
(no connection)
Ground
(no connection)
(TX Data + [XMT+])
(TX Data - [XMT-])
(no connection)
(Ground)
(no connection)

14
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
When connecting the twisted-pair cable from the
Converter’s RJ-45 jack to the RS-485 device, your cable
must be connected as shown in Table 4-1.
Table 4-1. Connecting the Twisted Pair to the RS-485 Device.
Converter RS-485 Device
Signal Pin # RS-485 Signal
N/C 1
GND* 2
N/C 3
XMT+ 4 - - - - - - - - - - - - - - - - - - - XMT A
XMT- 5 - - - - - - - - - - - - - - - - - - - XMT B
N/C 6
GND* 7
N/C 8
*Connection to GND is optional
4.2.2 C ONNECTING VIA THE
T ERMINAL B LOCK
The following instructions will tell you how to open the
case, connect the bare wires to the terminal blocks, and
fasten the strain-relief collar in place so that the wires
won’t pull loose.
1. Open the case by twisting it open with a small
plastic screwdriver.
2. Strip the outer insulation from the twisted pairs
about one inch from the end. See Figures 4-2
and 4-3.

15
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
Figure 4-2. Stripping the Outer Insulation.
3. Strip back the insulation on each of
the two twisted pair wires about 0.25".
Figure 4-3. Strip the insulation on each of the two twisted pair wires.
4. Connect the wires to XMT+ and XMT- (transmit
positive and negative) on the terminal block, care-
fully noting which color is positive, and which
color is negative.

16
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
5. Connect the same pair of wires to XMT A and
XMT B on the RS-485 device, respectively, as
shown in Table 4-2.
Table 4-2. Crossover Cable Connection.
Converter RS-485 Device
XMT+ - - - - - - - - - - - - - - - XMT A
XMT- - - - - - - - - - - - - - - - - XMT B
6. Place the two halves of the strain-relief assembly
on either side of the telephone wire and press
together very lightly. Slide the assembly so that it is
about 2 inches (5 cm) from the terminal posts and
press together firmly.
7. Insert the strain-relief assembly with the wire going
through it into the slot in the bottom half of the
Converter case and set it into the recess in the
case.

17
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
Figure 4-4. Inserting the strain-relief assembly.
8. Bend the top half of the case as necessary to place
it over the strain-relief assembly. Do not snap the
case together yet.
Figure 4-5. Placing the top half of the case
over the strain-relief assembly.

18
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
9. Insert one captive screw through a saddle washer
and then insert the captive screw with the washer
on it through the hole in the DB25 end of the
case. Snap that side of the case closed. Repeat
the process for the other side. Cable installation
is complete.

19
ASYNC RS-232 TO 2-WIRE RS-485 CONVERTER
5. Operation
Once the Converter is properly installed, it should
operate transparently—as if it were a standard cable
connection. The Converter derives operating power
from the RS-232 data and control signals; there is no
ON/OFF switch.