National Instruments GPIB-232CV-A User manual

GPIB
GPIB-232CV-A
User Manual
IEEE 488 RS-232 Converter
GPIB-232CV-A User Manual
November 1999 Edition
PartNumber370905A-01

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©Copyright 1992, 1999 National Instruments Corporation. All rights reserved.

Important Information
Warranty
The GPIB-232CV-A is warranted against defects in materials and workmanship for a period of two years from the date of
shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment
that proves to be defective during the warranty period. This warranty includes parts and labor.
The media on which you receive National Instruments software are warranted not to fail to execute programming instructions,
due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced by receipts or other
documentation. National Instruments will, at its option, repair or replace software media that do not execute programming
instructions if National Instruments receives notice of such defects during the warranty period. National Instruments does not
warrant that the operation of the software shall be uninterrupted or error free.
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of
the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of
returning to the owner parts which are covered by warranty.
National Instruments believes that the information in this document is accurate. The document has been carefully reviewed
for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to
make changes to subsequent editions of this document without prior notice to holders of this edition. The reader should consult
National Instruments if errors are suspected. In no event shall National Instruments be liable for any damages arising out of
or related to this document or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY
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INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR
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apply regardless of the form of action, whether in contract or tort, including negligence. Any action against National Instruments
must be brought within one year after the cause of action accrues. National Instruments shall not be liable for any delay in
performance due to causes beyond its reasonable control. The warranty provided herein does not cover damages, defects,
malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation, or
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Trademarks
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Product and company names mentioned herein are trademarks or trade names of their respective companies.
WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS
(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL
OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL
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(2) IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS
CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL
POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE
FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION,
INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR
FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC
SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF
THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER
COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD
CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH)
SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM
FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNER MUST TAKE
REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO
BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS
FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER
MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT
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SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND
SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

Compliance
FCC/Canada Radio Frequency Interference Compliance*
Determining FCC Class
The Federal Communications Commission (FCC) has rules to protect wireless communications from interference.
The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial-
commercial locations only) or Class B (for use in residential or commercial locations). Depending on where it is
operated, this product could be subject to restrictions in the FCC rules. (In Canada, the Department of
Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.)
Digital electronics emit weak signals during normal operation that can affect radio, television, or other wireless
products. By examining the product you purchased, you can determine the FCC Class and therefore which of the two
FCC/DOC Warnings apply in the following sections. (Some products may not be labelled at all for FCC, if so the
reader should then assume these are Class A devices.)
FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and
undesired operation. Most of our products are FCC Class A. The FCC rules have restrictions regarding the locations
where FCC Class A products can be operated.
FCC Class B products display either a FCC ID code, starting with the letters EXN,
or the FCC Class B compliance mark that appears as shown here on the right.
The curious reader can consult the FCC web site http://www.fcc.gov for more
information.
FCC/DOC Warnings
This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the
instructions in this manual and the CE Mark Declaration of Conformity**, may cause interference to radio and
television reception. Classification requirements are the same for the Federal Communications Commission (FCC)
and the Canadian Department of Communications (DOC).
Changes or modifications not expressly approved by National Instruments could void the user’s authority to operate
the equipment under the FCC Rules.
Class A
Federal Communications Commission
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to
radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in
which case the user will be required to correct the interference at his own expense.
Canadian Department of Communications
This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du
Canada.
Class B
Federal Communications Commission
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful

interference to radio or television reception, which can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
Canadian Department of Communications
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du
Canada.
European Union - Compliance to EEC Directives
Readers in the EU/EEC/EEA must refer to the Manufacturer's Declaration of Conformity (DoC) for information**
pertaining to the CE Mark compliance scheme. The Manufacturer includes a DoC for most every hardware product
except for those bought for OEMs, if also available from an original manufacturer that also markets in the EU, or
where compliance is not required as for electrically benign apparatus or cables.
* Certain exemptions may apply in the USA, see FCC Rules §15.103 Exempted devices, and §15.105(c). Also
available in sections of CFR 47.
** The CE Mark Declaration of Conformity will contain important supplementary information and instructions for
the user or installer.

©National Instruments Corporation vii GPIB-232CV-A User Manual
Contents
About This Manual
Conventions ...................................................................................................................xi
Related Documentation..................................................................................................xii
Chapter 1
Introduction
GPIB-232CV-A Overview ............................................................................................1-1
What You Need to Get Started ......................................................................................1-2
Optional Equipment.......................................................................................................1-2
Inspection.......................................................................................................................1-3
GPIB-232CV-A Panels..................................................................................................1-3
AC Front Panel................................................................................................1-3
Top Panel.........................................................................................................1-4
Rear Panel........................................................................................................1-5
Side Panels.......................................................................................................1-6
RS-232 Connector.............................................................................1-7
GPIB Connector................................................................................1-8
Chapter 2
Configure and Install Your Hardware
Configure Your Hardware .............................................................................................2-1
Configure the GPIB-232CV-A Parameters.....................................................2-2
Configure the Serial Port Parameters ..............................................................2-5
Install Your Hardware ...................................................................................................2-6
Step 1. Shut Down Your System.....................................................................2-6
Step 2. Verify That You Have a Null-Modem Serial Cable............................2-7
Step 3. Connect the Cables..............................................................................2-7
Step 4. Power on Your System and Switch on Your GPIB-232CV-A ...........2-8
Chapter 3
Operation of the GPIB-232CV-A
Choosing Between D Mode and C Mode Configuration...............................................3-1
When to Use D Mode......................................................................................3-1
When to Use C Mode......................................................................................3-2
D Mode Overview .........................................................................................................3-3
Data Transfers in D Mode...............................................................................3-3
Choosing a Serial Port Buffer Size..................................................................3-4

Contents
GPIB-232CV-A User Manual viii www.ni.com
Using the SRQ Feature ...................................................................................3-4
Conditions That Cause SRQ to be Asserted.....................................3-5
Maximizing Performance with SRQ ................................................3-5
GPIB-232CV-A Serial Poll Responses...........................................................3-6
GPIB-232CV-A Operation in Listen-Only Mode...........................................3-6
C Mode Overview .........................................................................................................3-7
Data Transfers in C Mode...............................................................................3-7
Modes of Operation Within C Mode ..............................................................3-8
Timeout Termination Mode..............................................................3-8
<CR> or <LF> Termination Mode................................................... 3-9
No-Swap Mode.................................................................................3-10
Data Buffering and Handshaking Schemes...................................................................3-11
Hardware Handshaking...................................................................................3-11
XON/XOFF Software Handshaking...............................................................3-12
Appendix A
Specifications
Appendix B
Interfacing to a Serial Device
Appendix C
Application Examples
Appendix D
Technical Support Resources
Glossary
Index
Figures
Figure 1-1. GPIB-232CV-A AC Front Panel ..........................................................1-3
Figure 1-2. GPIB-232CV-A Top Panel...................................................................1-4
Figure 1-3. GPIB-232CV-A Rear Panel..................................................................1-5
Figure 1-4. Location of the Connectors and the DC Power Jack ............................1-6
Figure 1-5. RS-232 Connector and Signal Designations.........................................1-7
Figure 1-6. GPIB Connector and Signal Designations............................................1-8

Contents
©National Instruments Corporation ix GPIB-232CV-A User Manual
Figure 2-1. Factory Default Switch Settings for SW1.............................................2-2
Figure 2-2. Factory Default Switch Settings for SW2.............................................2-5
Figure 3-1. Example of D Mode System Setup .......................................................3-2
Figure 3-2. Example of C Mode System Setup........................................................3-2
Figure 3-3. D Mode System Layout.........................................................................3-3
Figure 3-4. Switch Settings for Listen-Only Mode..................................................3-6
Figure 3-5. C Mode System Layout.........................................................................3-7
Figure 3-6. Timeout Termination Mode Cycle........................................................3-8
Figure B-1. Location of the RS-232 Connector........................................................B-3
Figure B-2. Cable Configuration for 9-pin DTE to 9-pin DCE
with Handshaking..................................................................................B-4
Figure B-3. Cable Configuration for 9-pin DTE to 25-pin DCE
with Handshaking..................................................................................B-4
Figure B-4. Minimum Configuration for 9-pin DTE to 9-pin DCE.........................B-5
Figure B-5. Minimum Configuration for 9-pin DTE to 25-pin DCE.......................B-5
Figure B-6. Cable Configuration for 9-pin DTE to 9-pin DTE
with Handshaking..................................................................................B-7
Figure B-7. Cable Configuration for 9-pin DTE to 25-pin DTE
with Handshaking..................................................................................B-7
Figure B-8. Minimum Configuration for 9-pin DTE to 9-pin DTE .........................B-8
Figure B-9. Minimum Configuration for 9-pin DTE to 25-pin DTE .......................B-8
Figure C-1. Example of Print Spooler Setup............................................................C-2
Tables
Table 1-1. LED Descriptions..................................................................................1-4
Table 2-1. Configuration Parameters for SW1 Switches 1 through 5 ....................2-2
Table 2-2. Configuration Parameters for SW1 Switches 6 and 7...........................2-4
Table 2-3. Configuration Parameters for SW1 Switch 8........................................2-4
Table 2-4. Configuration Parameters for SW2 Switches 1 through 3 ....................2-5
Table 2-5. Configuration Parameters for SW2 Switches 4 through 8 ....................2-6
Table 2-6. National Instruments Null-Modem Serial Cables .................................2-7
Table B-1. RS-232 Serial Port Signal Configuration..............................................B-2
Table B-2. Cable Wiring Scheme for GPIB-232CV-A DTE to
Serial Device DCE ................................................................................B-3
Table B-3. Cable Wiring Scheme for GPIB-232CV-A DTE to
Serial Device DTE.................................................................................B-6

©National Instruments Corporation xi GPIB-232CV-A User Manual
About This Manual
The GPIB-232CV-A User Manual describes the features, functions, and
operation of the GPIB-232CV-A. This manual assumes that you have a
general knowledge of RS-232 serial communications and the General
Purpose Interface Bus (GPIB).
Conventions
The following conventions appear in this manual:
This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a systemcrash.
bold Bold text denotes items that you must select or click on in the software,
such as menu items and dialog box options. Bold text also denotes
parameter names.
IEEE 488 and IEEE 488 and IEEE 488.2 refer to the ANSI/IEEE Standard 488.1-1987
IEEE 488.2 and the ANSI/IEEE Standard 488.2-1992, respectively, which define the
GPIB.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames and extensions, and code excerpts.
RS-232 RS-232 refers to the ANSI/EIA-232-C standard.

About This Manual
GPIB-232CV-A User Manual xii www.ni.com
Related Documentation
The following documents contain information that you might find helpful
as you read this manual:
• ANSI/EIA-232-C, Interface Between Data Terminal Equipment and
Data Circuit-Terminating Equipment Employing Serial Binary Data
Interchange
• ANSI/IEEE Standard 488.1-1987, IEEE Standard Digital Interface
for Programmable Instrumentation
• ANSI/IEEE Standard 488.2-1992, IEEE Standard Codes, Formats,
Protocols, and Common Commands

©National Instruments Corporation 1-1 GPIB-232CV-A User Manual
1
Introduction
This chapter describes the GPIB-232CV-A, lists what you need to get
started and optional equipment you can order, and describes the panels on
the GPIB-232CV-A.
GPIB-232CV-A Overview
The GPIB-232CV-A has a powerful 8-bit microcomputer tailored for use
as an IEEE 488-to-RS-232 protocol converter. Both the RS-232 serial port
and the GPIB (IEEE 488) port are interrupt-driven and feature extremely
fast response times to external data transfers. The GPIB-232CV-A can
transparently convert data between the two ports so that control codes or
special commands are not required. Data transfers in either direction are
possible at all times.
The GPIB-232CV-A microprocessor contains an integrated direct memory
access (DMA) controller for high-speed data transfers from the GPIB
circuitry. The GPIB-232CV-A also increases the efficiency of the interface
system by using a 256 KB RAM buffer to isolate the slower device from the
faster port. You can use the GPIB-232CV-A to interface either a GPIB
Controller or a GPIB device to a computer or instrument with a RS-232
port. The RS-232 serial port is fully compatible with all electrical
specifications in the RS-232 standard.
The operating system of the GPIB-232CV-A is contained in read-only
memory (ROM) and can address up to 256 KB of dynamic random-access
memory (RAM). The operating system programs and maintains the
LSI GPIB Controller chip, the NAT4882, which implements all IEEE 488
interface functions. The GPIB-232CV-A microprocessor contains an
integrated memory management unit, a dynamic RAM controller, a clock
generator, a programmable timer unit, a full duplex UART (Universal
Asynchronous Receiver Transmitter), and an interrupt controller.

Chapter 1 Introduction
GPIB-232CV-A User Manual 1-2 www.ni.com
What You Need to Get Started
Before you install your GPIB hardware, make sure you have all of the
following items:
❑One of the following boxes, which is included in your kit:
– GPIB-232CV-A (100-120 VAC)
– GPIB-232CV-A (220-240 VAC)
– GPIB-232CV-A (DC)
❑If you have the GPIB-232CV-A AC version, one of the following
power cords:
– U.S. standard power cord
– Swiss power cord
– Australian power cord
– Universal European power cord
– North American power cord
– U.K. power cord
❑If you have the GPIB-232CV-A DC version, one of the following:
– 9 V wall-mount power supply (100–120 VAC)
– 9 V wall-mount power supply (220–240 VAC)
❑Type XI or X2 single-shielded or double-shielded GPIB cable (1, 2, or
4 m), which you can purchase from National Instruments
Caution To meet FCC emission limits for this device, you must use a Type X2
double-shielded GPIB cable. If you operate this equipment with a non-shielded cable,
it may interfere with radio and television reception.
Optional Equipment
You can order a 9-pin, 2 m RS-232 shielded cable (GPIB-232CV-A to
IBM PC) from National Instruments.

Chapter 1 Introduction
©National Instruments Corporation 1-3 GPIB-232CV-A User Manual
Inspection
Before you operate the GPIB-232CV-A, inspect the shipping container and
its contents for damage. Keep the packing material for possible inspection
and/or reshipment.
If the equipment appears to be damaged, do not attempt to operate it.
Contact National Instruments for instructions. If the damage appears to
have been caused in shipment, file a claim with the carrier.
GPIB-232CV-A Panels
The following sections describe the panels of the GPIB-232CV-A.
AC Front Panel
The power switch, fuse holder, and power cord receptacle are located on
the GPIB-232CV-A front panel, on the AC version only. Figure 1-1 shows
the front panel of the AC version.
Figure 1-1. GPIB-232CV-A AC Front Panel
FUSE

Chapter 1 Introduction
GPIB-232CV-A User Manual 1-4 www.ni.com
Top Panel
The six light-emitting diodes (LEDs) are located on the GPIB-232CV-A
top panel. Figure 1-2 shows the top panel.
Figure 1-2. GPIB-232CV-A Top Panel
The LEDs show the current status of the GPIB-232CV-A. Table 1-1
describes each LED.
Table 1-1. LED Descriptions
LED Indication
POWER Indicates that power has been applied to the unit and
the ON/OFF switch is in the ON position.
READY Indicates that the power-on self-test has successfully
passed and the unit is ready to operate.
TALK Indicates that the GPIB-232CV-A is configured as a
GPIB Talker.
LISTEN Indicates that the GPIB-232CV-A is configured as a
GPIB Listener.
TALK
LISTEN BUSY FULL
GPIB-232CV-A
IEEE 488 ConverterRS-232
POWER READY

Chapter 1 Introduction
©National Instruments Corporation 1-5 GPIB-232CV-A User Manual
Rear Panel
The configuration switches are located on the rear panel of the
GPIB-232CV-A. The power switch of the DC version is also located on the
rear panel.
Figure 1-3 shows the rear panel of the GPIB-232CV-A.
Figure 1-3. GPIB-232CV-A Rear Panel
BUSY Indicates that the GPIB-232CV-A is currently
accepting serial data. Each serial character received
toggles the status of the BUSY LED.
FULL Indicates that one of the GPIB-232CV-A data buffers
is full. This is not an error condition, but is merely a
signal that bus performance may be reduced to the
speed of the slower port.
Table 1-1. LED Descriptions (Continued)
LED Indication
12345678
MODE
CONFIG
GPIB ADDRESS
O
N
BAUD RATE
DATA FORMAT
HANDSHAKE
12345678
O
N

Chapter 1 Introduction
GPIB-232CV-A User Manual 1-6 www.ni.com
Side Panels
The GPIB connector and the RS-232 connector are mounted on opposite
side panels. On the DC version, the DC power jack is on the same end as
the serial connector.
Figure 1-4 shows the location of the RS-232 and GPIB connectors and the
DC power jack.
Figure 1-4. Location of the Connectors and the DC Power Jack
POWER
READY
TALK
LISTEN
IEEE 488 ControllerRS-232
RS-232 Connector GPIB Connector
DC Power Jack
(DC version only)
BUSY
FULL
GPIB-232CV-A

Chapter 1 Introduction
©National Instruments Corporation 1-7 GPIB-232CV-A User Manual
RS-232 Connector
The RS-232 port on the GPIB-232CV-A is configured as a DTE (Data
Terminal Equipment) and uses a standard 9-pin shielded D-Subminiature
male connector with screwlock assemblies. The RS-232 connector accepts
standard 9-pin D-Subminiature female connectors. Figure 1-5 shows a
diagram of the serial connector and the signals supported. For more
information on the RS-232 signals refer to Appendix B, Interfacing to a
Serial Device.
Figure 1-5. RS-232 Connector and Signal Designations
No Connection
RTS
CTS
No Connection
No Connection
RXD
TXD
DTR
GND
23451
6789

Chapter 1 Introduction
GPIB-232CV-A User Manual 1-8 www.ni.com
GPIB Connector
TheGPIB connector is a standard24-pin shielded Champ female connector
with metric screwlock hardware. Figure 1-6 shows a diagram of the GPIB
connector and the signals supported. A * suffix indicates that the signal is
active low.
Figure 1-6. GPIB Connector and Signal Designations
DIO1*
DIO2*
DIO3*
DIO4*
EOI*
DAV*
NRFD*
NDAC*
IFC*
SRQ*
ATN*
SHIELD
1
2
3
4
5
6
7
8
9
10
11
12
DIO5*
DIO6*
DIO7*
DIO8*
REN*
GND (Twisted Pair with DAV*)
GND (Twisted Pair with NRFD*)
GND (Twisted Pair with NDAC*)
GND (Twisted Pair with IFC*)
GND (Twisted Pair with SRQ*)
GND (Twisted Pair with ATN*)
SIGNAL GROUND
13
14
15
16
17
18
19
20
21
22
23
24

©National Instruments Corporation 2-1 GPIB-232CV-A User Manual
2
Configure and Install
Your Hardware
This chapter describes how to configure and install your GPIB-232CV-A.
Configure Your Hardware
Before you configure your GPIB-232CV-A, verify that the voltage marked
on the GPIB-232CV-A or on the power supply matches the voltage that is
supplied in your area.
Caution Do not operate your GPIB-232CV-A at any voltage other than the one marked
on your GPIB-232CV-A. Doing so could damage the unit. Replacement fuses for the
AC version must be the proper type and size. For fuse specifications, refer to Appendix A,
Specifications.
Your GPIB-232CV-A is configured at the factory, as follows:
•Dmode
• GPIB primary address 5
• SRQ feature disabled
• Serial port is configured to:
– 9600 baud
– 1 stop bit per character
– Parity generation/checking disabled
– 7 data bits per character
– XON/XOFF protocol disabled
If you want to change any of the GPIB-232CV-A characteristics, you must
change the configuration switches. For information on choosing the mode
of operation, refer to Choosing Between D Mode and C Mode
Configuration in Chapter 3, Operation of the GPIB-232CV-A. Chapter 3
also contains information about choosing whether or not to use other
available features.

Chapter 2 Configure and Install Your Hardware
GPIB-232CV-A User Manual 2-2 www.ni.com
If you are already using the GPIB-232CV-A and decide to change its
operating characteristics, you must first shut down your system and then
continue with the following steps.
Configure the GPIB-232CV-A Parameters
You can use the DIP switches on the rear panel (see Figure 1-1,
GPIB-232CV-A AC Front Panel, and Figure 1-4, Location of the
Connectors and the DC Power Jack) to configure the GPIB-232CV-A.
Figure 2-1 shows the factory default setting for SW1.
Figure 2-1. Factory Default Switch Settings for SW1
In Figure 2-1, switches 1 through 5 are ON, OFF, ON, OFF, and OFF,
respectively, indicating a GPIB primary address of 5. Switches 6 and 7 are
in the OFF position, indicating that SRQ is disabled and the small serial
buffer is used. Switch 8 is in the OFF position, indicating that the unit is
configured to operate in D mode.
Tables 2-1, 2-2, and 2-3 show the possible configurations of SW1 and what
the configurations indicate. Default settings appear in bold italics.
Table 2-1. Configuration Parameters for SW1 Switches 1 through 5
Switches
Indication12345
OFF OFF OFF OFF OFF GPIB Primary Address 0
ON OFF OFF OFF OFF GPIB Primary Address 1
OFF ON OFF OFF OFF GPIB Primary Address 2
ON ON OFF OFF OFF GPIB Primary Address 3
OFF OFF ON OFF OFF GPIB Primary Address 4
SW1
12345678
MODE
CONFIG
GPIB ADDRESS
O
N