Dual Port RS-232/422/485 Serial Interface

MARCH 2000
IC113C
IC175C
Dual Port RS-232/422/485 Serial Interface
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 724-746-0746
Mail order: Black Box Corporation, 1000 Park Drive, Lawrence, PA 15055-1018
Web site: www.blackbox.com • E-mail: [email protected]
FCC AND IC STATEMENTS, TRADEMARKS
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 la classe A prescrites dans le Règlement sur le
brouillage radioélectrique publié par Industrie Canada.
TRADEMARKS USED IN THIS MANUAL
AT and IBM are registered trademarks, and XT is a trademark of
International Business Machines Corporation.
Any other trademarks mentioned in this manual are acknowledged to be the property
of the trademark owners.
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
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.
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.
NOM STATEMENT
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 equio 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.
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
Contents
Chapter
Page
1. Specifications...................................................................................................1
2. Introduction ....................................................................................................2
2.1 Overview ..................................................................................................2
2.2 What’s Included......................................................................................2
2.3 Features ...................................................................................................3
2.4 Technical Description ............................................................................4
3. Address Selection ............................................................................................6
4. Option Selection .............................................................................................7
4.1 Port Enable/Disable ...............................................................................7
4.2 RS-232 Interface Options .......................................................................9
4.3 RS-422/485 Interface Options .............................................................10
4.4 Line Termination .................................................................................11
5. Installation.....................................................................................................12
Appendix: Circuit-Board Design.......................................................................14
CHAPTER 1: Specifications
1. Specifications
Protocol — Asynchronous
Speed — IC113C: Up to 115.2 Kbps; IC175C: 460.8 kbps and higher
Operation — RS-232 or RS-485/422, 2- or 4-wire (individually selectable
on each port)
Connectors — (2) DB9M
Communications Chip — IC113C: 16550 UART; IC175C: 16950 UART
MTBF — >150,000 hours
MTTR — <0.25 hours
Materials — Boards are solder mask over bare copper or tin nickel
Operating Temperature — 32° to 122°F (0° to 50°C)
Storage Temperature — -4° to 158°F (-20° to 70°C)
Humidity — 0 to 90% relative humidity, noncondensing
Power — +5 VDC @ 195 mA ±12 V @ 25 mA (derived from PC bus)
Size — 5"W x 7.5 "D (12.7 x 19 cm)
Weight — 0.2 lb. (0.1 kg)
1
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
2. Introduction
2.1 Overview
If you need to operate RS-232, RS-422, or RS-485 devices from your PC, use
the Dual Port RS-232/422/485 Serial Interface. Connect to any device that
uses the RS-232 interface, such as modems, data-entry terminals, and plotters.
This card allows you to configure two RS-232 ports, two RS-422/485 ports, or
one of each. The Dual Port RS-232/422/485 also features greater maximum
distance and allows multi-drop communications.
The card also includes a serial utility disk with Seacom, a DOS interrupt and
driver package. Seacom allows data to be buffered, eliminating data loss in
high-speed data transfers. It also allows more than 4 ports (256 max.) to be
configured and utilized under DOS.
The README file on the serial utility disk contains information about the
latest changes and revisions. To view this file, insert the diskette into drive A
or B and type A:TYPE READ.ME|MORE [ENTER] or B:TYPE
READ.ME|MORE [ENTER].
2.2 What’s Included
Your Serial Interface should come with the following items. If any of these
items are missing or damaged, contact Black Box at 724-746-5500.
(1) Dual Port RS-232/422/485 Serial Interface card,
(2) serial utility software diskettes: (1) for 32-bit Windows®,
(1) for DOS and Windows®3.1x,
This manual
2
CHAPTER 2: Introduction
2.3 Features
Listed below are the special features your Serial Interface offers.
• Each port is independently addressable.
• Eleven interrupt options, including AT interrupts, for simple integration
into existing systems.
• IRQs (2 [9], 3, 4, 5, 6, 7, 10, 11, 12, and 15) supported.
• IRQs can be shared or individually set for each port.
• Supports Interrupt Sharing—only one interrupt line required for
multiple ports.
• Supports any character set defined by binary notation.
• 16550 UARTs on the IC113C help ensure against data loss. This chip
features programmable baud rate, data format, interrupt control, and a
16-byte FIFO. The IC175C uses 16950 UARTs, which feature a 128-byte
buffer for even better performance.
• Faster baud rates—up to 115.2 Kbps (IC113C) or 460.8 kbps and above
(IC175C).
• Addressable as COM1: through COM4: or any other address up
to 3FF Hex.
• Support for non-standard baud rates available. These baud rates (such as
31.25K or 76.8K baud) are supported by installing a different oscillator at
location Y1. Call Technical Support for more information.
3
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
2.4 Technical Description
The Dual Port RS-232/422/485 Serial Interface utilizes the same 16550 UART
chip found in the IBM® asynchronous adapter. This chip features
programmable baud rate, data format, and interrupt control. Refer to the
IBM Technical Reference for details on programming the chip.
RS-232
The Dual Port RS-232/422/485 Serial Interface meets the RS-232C
specifications and provides an asynchronous serial I/O port. This is the
standard port configuration found in the IBM AT® computer, including the
DB9 style connector.
The table below shows the connector pinouts for ports J1 (port 1) and J2
(port 2) on the Interface while using RS-232.
Pin Number
Signal Name
Mode
3
7
4
5
2
1
6
8
9
Transmit Data (TD)
Request To Send (RTS)
Data Term Ready (DTR)
Ground (GND)
Receive Data (RD)
Data Carrier Detect (DCD)
Data Set Ready (DSR)
Clear To Send (CTS)
Ring Indicator (RI)
Output RS-232
Output RS-232
Output RS-232
––––––––––––
Input RS-232
Input RS-232
Input RS-232
Input RS-232
Input RS-232
RS-422
RS-422 allows very long distance communications—4000 feet (about
1219 meters) at 9600 baud—based on use of Category 3, UTP, or better, with
virtually error-free differential drive characteristics. RS-422 signal levels are
the standard electrical specification used in RS-449 and EIA-530. This allows
interfacing with equipment that meets these specifications.
4
CHAPTER 2: Introduction
RS-485
RS-485 is backward-compatible with RS-422; however, it is optimized for
multidrop applications. The output of the RS-422/485 driver is capable of
being active (enabled) or tri-state (disabled). This capability allows multiple
ports to be connected in a multidrop bus and selectively polled. Half-duplex
two-wire communications are possible by connecting TX+ to RX+ and TX- to
RX- in your cable connector. The enable to the driver is connected to the
UART Request To Send (RTS) line for RS-485 communications. This allows
the RS-485 driver to be tri-stated (disabled) when inactive on a multidrop
polled network. The software that you are using must “know how” to enable
the driver when it is answering a poll. Failure to set this jumper correctly can
cause transmitter contention problems, preventing operation by any nodes on
the network.
The table below shows the connector pinouts for ports J1 (port 1) and J2
(port 2) on the Interface while using RS-422/485.
Pin Number
Signal Name
Mode
4
3
6
7
5
1
2
9
8
Transmit Data Pos. (TX+)
Transmit Data Neg. (TX-)
Req. To Send Pos. (RTS+)
Req. To Send Neg. (RTS-)
Ground (GND)
Receive Data Pos. (RX+)
Receive Data Neg. (RX-)
Clear To Send Pos. (CTS+)
Clear To Send Neg. (CTS-)
Output RS-422
Output RS-422
Output RS-422
Output RS-422
-------------------Input RS-422
Input RS-422
Input RS-422
Input RS-422
5
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
3. Address Selection
NOTE
Be sure to set the address selections and jumper options before
installation.
Each serial port on the Dual Port RS-232/422/485 Serial Interface occupies
8 consecutive I/O locations. DIP switch SW1 sets the base address for Port 1,
and DIP switch SW2 sets the address for Port 2. Be careful when selecting the
base address, since some selections conflict with existing PC ports. The
following table shows several examples that usually do not cause a conflict.
Address
Binary
Hex
280-287
2A0-2A7
2E8-2EF
2F8-2FF
3E8-3EF
300-307
328-32F
3F8-3FF
A9
A0
1010000XXX
1010100XXX
1011101XXX
1011111XXX
1111101XXX
1100000XXX
1100101XXX
1111111XXX
Switch Position Setting
1
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
2
ON
ON
ON
ON
OFF
OFF
OFF
OFF
3
OFF
OFF
OFF
OFF
OFF
ON
ON
OFF
4
ON
ON
OFF
OFF
OFF
ON
ON
OFF
5
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
6
ON
ON
ON
OFF
ON
ON
ON
OFF
7
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
Typically COM1:=3F8h; COM2:=2F8h; COM3:=3E8h; COM4:=2E8h
The following illustration shows the correlation between the DIP switch
setting and the address bits used to determine the base address. In the figure
below, the address 300 hex through 307 hex is selected (300 hex =11 0000
0XXX in binary representation). Note that setting the switch ON (or closed)
corresponds to a “0” in the address, while leaving it OFF (or open)
corresponds to a “1.”
A9
A3 EN
0
ON
1
OFF
1
6
2
3
4
5
6
7
8
CHAPTER 4: Option Selection
4. Option Selection
NOTE
Be sure to set the address selections and jumper options before
installation.
The board contains several jumper straps for each port which must be set for
proper operation.
4.1 Port Enable/Disable
Each port on the Dual Port RS-232/422/485 can be enabled or disabled with
switch position 8 on the DIP switch. The port is enabled with the switch ON
(or closed) and disabled when OFF (or open). If any port is disabled, be sure
to also disable the interrupt request for that port by removing the IRQ jumper
(see Figure 4-1).
INTERFACE SELECTION
RS-422/485
To select the RS-422/485 mode of operation, install DIP shunts in sockets
found at E6 and E7. E6 sets Port 1 and E7 sets Port 2.
RS-232
To select the RS-232 mode of operation, install DIP shunts in sockets found
at E5 and E8. E5 sets Port 1 and E8 sets Port 2.
IRQ Selection
Headers E1 and E2 select the interrupt request for each serial port (E1–Port
2, E2–Port 1). If COM1: is selected, this jumper must be on the IRQ4 setting.
If COM2: is selected, this jumper must be on IRQ3.
NOTE
Most communications software applications default COM3: to IRQ4 and
COM4: to IRQ3. This requires the sharing of interrupts between COM1:
and COM3:, and between COM2: and COM4:. While this is the default, it
is not always the best setting. Check your software configuration
instructions to determine the most appropriate IRQ setting.
7
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
E1
2/9 3
4
5
7 10 11 12 15
2/9 3
4
5
7 10 11 12 15
E2
Figure 4-1. Header E1 and E2 (IRQ selection).
Any two or more ports can share a common IRQ by placing the jumpers on
the same IRQ setting, and setting the appropriate selections at E9 and E10.
Consult your particular software for IRQ selection. If no interrupt is desired,
remove the jumper.
NOTE
IRQ 2 on AT class machines is not available. IRQ 9 is substituted in place
of IRQ 2. To select IRQ 9, place jumper in the IRQ 2 position.
Figure 4-2 shows Headers E9 and E10. “N” indicates the normal, single
interrupt per port mode. The “S” indicates the shared interrupt mode, which
allows more than one port to access a single IRQ. The “M” indicates that the
inclusion of a 1K-ohm pull-down resistor is required on one port when
sharing interrupts. E10 sets Port 1 and E9 sets Port 2.
8
M
S
N
CHAPTER 4: Option Selection
Figure 4-2. Headers E9 and E10 in Normal Mode.
Set jumpers to “N” for single interrupt mode. This setting is the normal
setting for most applications.
Set jumpers to “S” for shared interrupt mode for all ports sharing an IRQ
except one. Set that port block for “M.” This provides the pull-down resistor
circuit that makes sharing of IRQ’s possible. If you are using more than one Dual
Port RS-232/422/485 Serial Interface or a compatible card in a bus, you should only
have one port set to “M.”
Set jumpers to “S” if you are using more than one Dual Port
RS-232/422/485 in a bus or if you wish to completely remove the pull-down
resistor for hardware compatibility. Setting the board in this configuration
when it is not accompanied by a pull-down resistor will prevent the ports from
triggering an interrupt.
4.2 RS-232 Interface Options
To select the RS-232 mode of operation, install DIP shunts in the sockets
found at E5 and E8. E5 sets Port 1 and E8 sets Port 2. These DIP shunts are
completely independent of each other, allowing the user to select a singleport RS-232 or a single-port RS-422.
There are no modem control options for the RS-232 interface: all control
signals are implemented. If your software requires certain handshaking
signals to be active, then you must connect them either to the device with
which you are communicating or you can satisfy the handshake signal
requirements by connecting pins 7 to 8 (RTS to CTS) and pins 4 to 6 to 1
(DTR to DSR & DCD). Make these connections on the DB9 connector that
connects to each port. Refer to Figure 4-3 when making these connections.
(The table on page 4 lists the RS-232 pinout descriptions.)
9
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
5
4
9
3
8
2
7
1
6
Figure 4-3. DB9 Handshake Loopback connections for RS-232
(shown from rear or cable side of connector).
4.3 RS-422/485 Interface Options
To select the RS-422/485 mode of operation, install DIP shunts in the sockets
found at E6 and E7. E6 sets Port 1 and E7 sets Port 2.
Figure 4-4 shows Headers E3 and E4. Position “A” determines whether the
RS-485 driver is enabled by the UART signal Request To Send (RTS) or always
enabled. With the jumper installed in position “A,” RTS enables the driver.
Removing the jumper enables the driver, regardless of RTS. E4 sets Port 1
and E3 sets Port 2. This jumper should be set to “A” only if you are running
the board in a multidrop polled environment such as RS-485, and you have
software that “knows how to talk” on the RS-485 bus. For normal point-topoint RS-422 (such as terminal emulation), make sure that a jumper at
position “A” is not in place.
Positions “B” and “C” determine whether the board provides a direct ground
connection (as in RS-232 and most RS-422), or a 100-ohm high-impedance
ground. The high-impedance ground is normally used by
RS-485 (and some RS-422) to avoid ground-loop currents with long cables.
Position “B” selects the direct ground, and position “C” selects the 100-ohm
high-impedance ground. “C” should be selected when RS-422/485 operation
is selected.
10
A
B
C
CHAPTER 4: Option Selection
Figure 4-4. Headers E3 and E4, RS-485 Enable/Ground Selection.
4.4 Line Termination
Typically each end of the RS-422/485 bus must have line-terminating
resistors. A 100-ohm resistor is across each RS-422/485 input, and a 1K-ohm
pull-up/pull-down combination biases the receiver inputs. If more than two
RS-485 nodes are configured in a multidrop network, only the nodes at each
end of the bus should have the 100-ohm resistors installed.
11
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
5. Installation
The Dual Port RS-232/422/485 can be installed in any of the PC expansion
slots, except J8 on the original IBM XT® and Portable.
IMPORTANT
You MUST set up the operating system BEFORE you physically install
the Card.
5.1 Software Installation
If you are installing an ISA adapter in DOS, OS/2®, or QNX, please refer to the
appropriate directory on one of the Serial Utilities Disks for instructions.
5.1.1 WINDOWS 3.1X
Please refer to the /WINDOWS sub-directory on the Serial Utilities Diskette for
help files and current information on the installation of the Card in this operating
environment.
5.1.2 WINDOWS 95/98 USERS
For the ISA card, run setup on disk two of the Serial Utilities Diskettes before
installing the card. Make note of the resources that Windows assigns the adapter,
and set the adapter to match those resources. Power down the computer and
install the adapter as described in Section 5.2. If you wish to change any resources
assigned to the adapter, refer to the help file installed in the Black Box folder in
the Start, Programs menu.
5.1.3 WINDOWS NT
For the ISA card, run setup on disk two of the Serial Utilities Diskettes before
installing the card. After installing the software, refer to the help file that
automatically comes up for installation instructions.
12
CHAPTER 5: Installation
5.2 Hardware Installation
The ISA Card can be installed in any of the PC expansion slots. The Card contains
several jumper straps for each port that you must set for proper operation.
1. Turn off PC power. Disconnect the power cord.
2. Remove the PC case cover.
3. Locate an available slot and remove the blank metal slot cover.
4. Gently insert the Card into the slot. Make sure that the Card is seated
properly.
5. Replace the screw.
6. Replace the cover.
7. Connect the power cord.
Installation is complete.
Self-Test
To perform a self-test on the card, connect the transmit and receive data pins
together. If running 422/485, make sure the plus leads are not connected to
the minus leads. Execute the SLT program provided on the supplied utility
diskette.
13
14
C1
C1
SW1
V1
C5
U4
U5
PORT1
R1
U1
PORT1
C3
SW2
PORT2
C2
U2
PORT2
R2
P6
P2
PORT2
PORT1
E1
E2
U3
PORT2 PORT1
E9
E10
2
2
R4 R5
3
3 D1 R3 D2
4
4
5
5
6
6
10
10
11
11
12
12
15
15
C7
C8
C6
E3
PORT2
R7
A
B
C
RP1
U6
U7
RP4
RP2 RP3
U11
A
B
R6
C
E4
PORT1
U18
U8
U9
R9
R8
P1
P3
C9
E8
E7
U12
E6
E5
U13
RS-232 PORT 2
422/485 PORT 2
RS-232 PORT 1
422/485 PORT 1
C10
J1 PORT 2
1
6
J1 PORT 1
5
9
1
6
5
9
Appendix: Circuit-Board Design
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
A4
A3
A2
P1
P1
P1
D6
A5
P1
P2
A6
P1
P2
A7
P1
D4
A8
P1
B21
A9
P1
P1
B14
P1
D5
B13
P1
P2
A29
P1
D3
A30
P1
P2
A31
P1
B23
B2
P1
P1
A28
P1
B4
A27
P1
B24
A26
P1
B25
A25
P1
P1
A24
P1
P1
A23
P1
P1
A22
P1
IRQ15
IRQ11
IRQ7
IRQ12
IRQ10
IRQ5
IRQ4
IRQ3
D7
D6
2
4
6
8
10
12
14
16
18
2
4
6
8
10
12
14
16
18
1
3
5
7
9
11
13
15
17
19
1
E2
1
3
5
7
9
11
13
15
17
GND
GND
3
4
5
6
7
8
9
D5
E1
GND
BRD
11
13
15
17
19
2
4
6
8
1
3
5
7
9
12
14
16
18
2
SHEET 1
2
1
SW1
16
R5
3
SW1
14
1
5
SW1
12
GND
D4
+5V
7
SW1
10
6
4
2
D3
D2
D1
D0
RD/
WR/
A2
A1
A0
RESET
IRQ2
GND
SW1
SW1
SW1
13
11
15
A4
A3
A5
A6
A7
A8
VSS
P>Q
P=Q
VDO
U1
U6
B1
2
2
R4
R3
B2
A2
B3
A3
B4
A4
B5
A5
B6
A6
B7
A7
B8
A8
74LS245
A1
VSS
VDO
U12
HC244
Y1
Y2
Y3
Y4
VDO/VSS
U3
HC244
5
4
20
10
1
19
20
1
1
17
16
15
14
13
12
11
18
10
20
9
7
5
3
10
Y1 18
16
Y2
14
Y3
12
Y4
VDO/VSS
G
DIR
A1
A2
A3
A4
G
A1
A2
A3
A4
G
U3
74LS125A
6
74LS682
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
P0
P1
P2
P3
P4
P5
P6
P7
9
GND
+5V
GND
1
BD1
BD2
BD3
BD4
BD5
BD6
BD7
1
8
R1
D2
D1
SW1
BD0
BWR/
BRD/
BRESET
BA0
BA1
BA2
+5V
GND
GND
+5V
1
2
2
2
GND
7
5
3
1
SW2
SW2
SW2
SW2
10
12
14
16
U6
74LS125A
8
U6
74LS125A
11
2
6
9
10
12
4
1
1
GND
GND
1
13
+5V
74LS125A
2
1
6
SW2
11
U6
4
SW2
13
3
2
SW2
15
A8
A6
A4
AEN
A3
A5
A7
A9
3
5
7
9
12
14
16
18
2
4
6
8
11
13
15
17
VSS
P>Q
P=Q
VDO
U2
10
1
+5V
GND
19
20
SHEET 2
SHEET 2
BD0
BD1
BD2
BD3
BD4
BD5
BD6
BD7
SHEET 2
TD1
DTR1
RTS1
GND
+5V
GND
TD2
7
1
1
2
3
4
5
6
7
8
33
32
34
31
24
23
15
30
11
SW2
8
NC
8250A
8
8250A
XTAL1
VSS XTAL2
MR
D0
CS0
D1
CS1
D2
CS2
D3
DISTR
D4
DISTR
D5
DOSTR
D6
DOSTR
D7
ADS
DTR
RCLK
RTS
SIN
OUT1
CTS
OUT2
DSR
CSOUT DCD
DDIS
RI
BAUDOUT A0
INTRPT
A1
SOUT
A2
VDO
U4
TXCO
OUT
VDO
Y1
14
XTAL1
XTAL2
MR
D0
CS0
D1
CS1
D2
CS2
D3
DISTR
D4
DISTR
D5
DOSTR
D6
DOSTR
D7
ADS
DTR
RCLK
RTS
SIN
OUT1
CTS
OUT2
DSR
CSOUT DCD
DDIS
RI
BAUDOUT A0
INTRPT
A1
SOUT
A2
U5
VSS
VDO
9
VSS
20
40
1
2
3
4
5
6
7
8
33
32
34
31
24
23
15
30
11
20
40
GND
+5V
DTR2
SHEET 2 RTS2
BD0
BD1
BD2
BD3
BD4
BD5
BD6
BD7
74LS682
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
P0
P1
P2
P3
P4
P5
P6
P7
R2
16
17
35
12
13
14
22
21
19
18
25
9
10
36
37
38
39
28
27
26
+5V
16
17
35
12
13
14
22
21
19
18
25
9
10
36
37
38
39
28
27
26
+5V
1
GND
2
+5V
RP1
2
4
6
8
11
13
15
17
RP1
A9
A8
A6
A4
AEN
A3
A5
A7
A9
RP1
AEN
4
3
2
1
4
3
2
1
A11
E9
E10
P1
BRESET
BA0
BA1
BA2
BWR/
BRD/
+5V
BRESET
BA0
BA1
BA2
GND
BWR/
BRD/
+5V
RD1
CTS1
DSR1
DCD1
RI1
RD2
CTS2
DSR2
DCD2
RI2
SHEET 2
SHEET 2
P1
P1
P1
B7
B31
B1
B29
B3
P1
P1
B9
P1
-12V
GND
GND
C10
+5V
+5V
+12V
2
1
C8
2
3
1
C9
-12V
2
3
1
+12V
2
3
1
2
3
1
C7
C1
C4
C6
GND
2
3
1
+5V
2
3
1
2
3
1
C5
2
3
1
C2
GND
2
3
C3
+5V
1
APPENDIX: Circuit-Board Design
15
9
7
8
1
3
4
J1
J1
J1
J1
J1
J1
6
9
7
J2
J2
J2
8
1
3
4
J2
J2
J2
J2
SHEET 1
2
J2
SHEET 1
6
J1
DTR2/
TD2/
DCD2/
CTS2/
RD2
CTS2
DSR2
DCD2
RTS2/
RI2/
DSR2/
RD2/
DTR1/
RD1
CTS1
DSR1
DCD1
TD1/
DCD1/
CTS1/
RTS1/
RI1/
DSR1/
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
1
2
3
4
5
6
7
8
9
10
11
12
RS-232
E8
RS-422
E7
RS-422
E6
24
23
22
21
20
19
18
17
16
15
14
13
24
23
22
21
20
19
18
17
16
15
14
13
24
23
22
21
20
19
18
17
16
15
14
13
U11-15
U11-13
U11-11
U10-3
GND
U9-11
U9-13
GND
U9-5
U9-3
U8-15
U8-13
U8-11
U10-11
SHEET 2
SHEET 2
SHEET 2
SHEET 2
R8
R9
2
1
-12V
7
4
2
VSS
4A
3A
2A
1A
75174
11
8
6
3
11
10
9
6
7
8
MC145406
12
5
13
14
4
15
16
2
VEE- VSS
8
15
9
7
1
3
VEE+ VDO
U11
RP2
RP2
RP2
RP2
+5V
9
10
11
12
13
14
15
16
VDO 16
U13
1Y
1Z
2Y
2Z
3Y
3Z
4Y
4Z
EN1
EN2
1
+12V
OUTD
OUTC
OUTB
OUTA
MC1489
V+
ENA
INA
ENB
INB
ENC
INC
END
IND
GND
U10
MC145406
VEE- VSS
1
5
U8
VEE+ VDO
1
2
3
6
5
10
11
14
13
4
12
14
2
1
5
4
9
10
12
13
7
8
7
6
5
4
3
2
1
1
GND
+5V
-12V
+12V
RP4
1
RP4
-12V
RP4
24
23
22
21
20
19
18
17
16
15
14
13
GND
+5V
U11-11
U11-13
DTR2
U11-15
75173
1A
16
1B VDO
2A
3
2B
1Y
5
3A
2Y
3B
3Y 11
13
4A
4Y
4B
8
EN VSS
EN
U9
GND
SHEET 2
SHEET 2
SHEET 1
SHEET 2
SHEET 1
SHEET 2
SHEET 1
SHEET 2
SHEET 2
SHEET 2
SHEET 1
SHEET 2
2
1
6
7
10
9
14
15
4
12
8
4
7
3
1
1
1
U10-11
U10-3
DTR1
U8-11
RTS1
U8-13
TD1
U8-15
1
GND
+5V
GND
+5V
RP3
E5
RP3
RS-232
RP3
1
2
3
4
5
6
7
8
9
10
11
12
RP4
8
6
4
1
7
5
3
2
RP3
RD1/
GND
+5V
J2
5
J1
9
RP1
SHEET 2
SHEET 1
SHEET 1
SHEET 1
RP1
U9-3
U9-5
U9-11
U9-13
TD2
RTS2
RI1
RI2
5
3
U7
8
6
GND2/
+5V
5
74LS04
U7
5
GND1/
74LS04
A
B
C
A
B
C
1
3
5
1
3
5
E3
E4
2
4
6
2
4
6
GND
GND
2
2
R6
RP4
R7
RP4
1
1
6
8
2
1
1
1
1
16
J1
GND
+5V
GND
+5V
GND
13
11
3
1
U7
U7
U7
U7
74LS04
12
74LS04
10
74LS04
4
74LS04
2
SPARE GATES
DUAL PORT RS-232↔422/485 SERIAL INTERFACE
© Copyright 2000. Black Box Corporation. All rights reserved.
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