National Instruments GPIB-110 User manual

© Copyright 1986, 1994 National Instruments Corporation.
All Rights Reserved.
GPIB-110
User Manual
August 1994 Edition
Part Number 320052-01

National Instruments Corporate Headquarters
6504 Bridge Point Parkway
Austin, TX 78730-5039
[phone]
Technical support fax: [phone]
[phone]
Branch Offices:
Australia [phone], Austria [phone], Belgium 02/757.00.20, Canada (Ontario) [phone],
Canada (Québec) [phone], Denmark 45 76 26 00, Finland (90) 527 2321, France (1) 48 14 24 24,
Germany 089/741 31 30, Italy 02/48301892, Japan [phone], Netherlands 03480-33466, Norway 32-848400,
Spain (91) 640 0085, Sweden 08-730 49 70, Switzerland 056/20 51 51, U.K. 0635 523545

Limited Warranty
The GPIB-110 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.
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 manual 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 WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. CUSTOMER'S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART
OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER.
NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS,
USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY
THEREOF. This limitation of the liability of National Instruments will 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 maintenance instructions; owner's modification of the product; owner's abuse, misuse, or negligent acts; and
power failure or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.
Copyright
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or
mechanical, including photocopying, recording, storing in an information retrieval system, or translating, in whole
or in part, without the prior written consent of National Instruments Corporation.
Trademarks
Product and company names listed are trademarks or trade names of their respective companies.
Warning Regarding Medical and Clinical Use
of National Instruments Products
National Instruments products are not designed with components and testing intended to ensure a level of reliability
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products involving
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by errors on
the part of the user or application designer. Any use or application of National Instruments products for or involving
medical or clinical treatment must be performed by properly trained and qualified medical personnel, and all
traditional medical safeguards, equipment, and procedures that are appropriate in the particular situation to prevent
serious injury or death should always continue to be used when National Instruments products are being used.
National Instruments products are NOT intended to be a substitute for any form of established process, procedure, or
equipment used to monitor or safeguard human health and safety in medical or clinical treatment.

FCC/DOC Radio Frequency Interference Compliance
This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the
instructions in this manual, may cause interference to radio and television reception. This equipment has been tested
and found to comply with the following two regulatory agencies:
Federal Communications Commission
This device complies with Part 15 of the Federal Communications Commission (FCC) Rules for a Class A digital
device. Operation is subject to the following two conditions:
1. This device may not cause harmful interference in commercial environments.
2. This device must accept any interference received, including interference that may cause undesired operation.
Canadian Department of Communications
This device complies with the limits for radio noise emissions from digital apparatus set out in the Radio
Interference Regulations of the Canadian Department of Communications (DOC).
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 édicté par le ministère des
communications du Canada.
Instructions to Users
These regulations are designed to provide reasonable protection against harmful interference from the equipment to
radio reception in commercial areas. 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.
There is no guarantee that interference will not occur in a particular installation. However, the chances of
interference are much less if the equipment is installed and used according to this instruction manual.
If the equipment does cause interference to radio or television reception, which can be determined by turning the
equipment on and off, one or more of the following suggestions may reduce or eliminate the problem.
• Operate the equipment and the receiver on different branches of your AC electrical system.
• Move the equipment away from the receiver with which it is interfering.
• Reorient or relocate the receiver’s antenna.
• Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated with
a cheater plug.
Notice to user: Changes or modifications not expressly approved by National Instruments could void the user’s
authority to operate the equipment under the FCC Rules.
If necessary, consult National Instruments or an experienced radio/television technician for additional suggestions.
The following booklet prepared by the FCC may also be helpful: How to Identify and Resolve Radio-TV
Interference Problems. This booklet is available from the U.S. Government Printing Office, Washington, DC
20402, Stock Number 004-000-00345-4.

© National Instruments Corporation v GPIB-110 User Manual
Contents
About This Manual.............................................................................................................ix
Organization of This Manual.........................................................................................ix
Conventions Used in This Manual.................................................................................x
Related Documentation..................................................................................................x
Customer Communication .............................................................................................x
Chapter 1
Description of the GPIB-110...........................................................................................1-1
What Your Kit Should Contain......................................................................................1-3
Optional Equipment.......................................................................................................1-4
Unpacking......................................................................................................................1-4
Chapter 2
Configuration and Installation.......................................................................................2-1
Grounding Configuration...............................................................................................2-1
The GPIB-110 Front and Rear Panels............................................................................2-3
The GPIB-110 Front Panel ................................................................................2-3
The GPIB-110 Rear Panel..................................................................................2-4
GPIB-110 Setup.............................................................................................................2-5
Cable Selection ..............................................................................................................2-6
Coaxial Cable Setup...........................................................................................2-6
Fiber Optic Cable Setup.....................................................................................2-7
Master Switch Setting....................................................................................................2-7
Fiber Optic Transmit Power...............................................................................2-7
Transmit Clock...............................................................................................................2-8
Extension Modes............................................................................................................2-8
Immediate Extension Mode...............................................................................2-8
IFC Wait Mode ..................................................................................................2-9
Parallel Poll Response (PPR) Modes.............................................................................2-9
Latched PPR Mode (Approach 1)......................................................................2-10
Unlatched PPR Mode (Approach 2) ..................................................................2-10
Mixed Mode Option...........................................................................................2-10
Installation......................................................................................................................2-11
Mounting........................................................................................................................2-11
Power On........................................................................................................................2-11
Self-Test Mode...............................................................................................................2-11
Self-Test with Coaxial Cable.............................................................................2-12
Self-Test with Fiber Optic Cable.......................................................................2-12
Connecting to Hewlett-Packard (HP) Controllers .........................................................2-13
Chapter 3
Theory of Operation ..........................................................................................................3-1
Extension Circuitry........................................................................................................3-2
Power On............................................................................................................3-2

Contents
GPIB-110 User Manual vi © National Instruments Corporation
System Controller Detection..............................................................................3-3
Active Controller Detection...............................................................................3-3
Source Handshake Detection.............................................................................3-3
Parallel Polling...................................................................................................3-4
Data Direction Control.......................................................................................3-5
EOI.....................................................................................................................3-5
SRQ....................................................................................................................3-5
Serial Communication Circuitry....................................................................................3-6
Link Establishment Protocol..............................................................................3-6
Serial Communication Protocol.........................................................................3-6
Packet Format ........................................................................................3-7
Receive Wait State.................................................................................3-7
Receive Packet State..............................................................................3-7
Transmit Synchronization State.............................................................3-7
Transmit Packet State.............................................................................3-7
Error Detection and Recovery............................................................................3-7
System Timing and Transmission Clock...........................................................3-8
Appendix A
Hardware Specifications...................................................................................................A-1
System Configuration ....................................................................................................A-1
Performance Characteristics ..........................................................................................A-1
Operating Characteristics...............................................................................................A-2
Electrical Characteristics................................................................................................A-2
Environmental Characteristics.......................................................................................A-3
Physical Characteristics .................................................................................................A-3
Appendix B
Multiline Interface Messages..........................................................................................B-1
Appendix C
Operation of the GPIB......................................................................................................C-1
History of the GPIB .......................................................................................................C-1
Types of Messages.........................................................................................................C-1
Talkers, Listeners, and Controllers................................................................................C-1
Controller-in-Charge and System Controller.................................................................C-2
GPIB Signals and Lines.................................................................................................C-2
Data Lines..........................................................................................................C-3
Handshake Lines................................................................................................C-3
NRFD (not ready for data).....................................................................C-4
NDAC (not data accepted).....................................................................C-4
DAV (data valid)....................................................................................C-4
Interface Management Lines..............................................................................C-4
ATN (attention)......................................................................................C-4
IFC (interface clear)...............................................................................C-4
REN (remote enable) .............................................................................C-4
SRQ (service request) ............................................................................C-4
EOI (end or identify)..............................................................................C-4

Contents
GPIB-110 User Manual vii © National Instruments Corporation
Physical and Electrical Characteristics..........................................................................C-5
Configuration Restrictions: The Role of Extenders and Expanders.............................C-7
Appendix D
Customer Communication...............................................................................................D-1
Glossary......................................................................................................................Glossary-1
Index..................................................................................................................................Index-1
Figures
Figure 1-1. The Model GPIB-110 Bus Extender.................................................................1-1
Figure 1-2. Typical GPIB-110 Extension System (Physical Configuration)......................1-2
Figure 1-3. Typical GPIB-110 Extension System (Logical Configuration)........................1-2
Figure 2-1. Isolation Selection ............................................................................................2-2
Figure 2-2. Rear Panel.........................................................................................................2-4
Figure 2-3. Configuration Switch........................................................................................2-5
Figure 2-4. GPIB-110 Label................................................................................................2-5
Figure 2-5. Internal Cable Selection Jumper (Shown for Coaxial Cable)...........................2-6
Figure 3-1. GPIB-110 Block Diagram ................................................................................3-2
Figure C-1. GPIB Cable Connector.....................................................................................C-3
Figure C-2. Linear Configuration of the GPIB Devices......................................................C-5
Figure C-3. Star Configuration of GPIB Devices................................................................C-6
Tables
Table 2-1. Transmit Clock Values Versus Cable Length ..................................................2-8
Table A-1. Performance Versus Distance...........................................................................A-1
Table A-2. Electrical Specifications...................................................................................A-3

© National Instruments Corporation ix GPIB-110 User Manual
About This Manual
The GPIB-110 User Manual describes how to install, configure, and operate the GPIB-110. The
GPIB-110 is a high-performance bus extender that converts IEEE 488 signals into data packets
for transmission to a matching GPIB-110, using a serial communication link to the distant
extender. The receiving extender converts the packets back to IEEE 488 signals.
Organization of This Manual
This manual is organized as follows:
• Chapter 1, Description of the GPIB-110, contains general information about the National
Instruments GPIB-110, lists the contents of the GPIB-110 kit, and explains how to unpack
the GPIB-110 kit.
• Chapter 2, Configuration and Installation, contains instructions for configuring, installing,
and verifying the operation of the GPIB-110.
• Chapter 3, Theory of Operation, contains an overview of the GPIB-110 and explains the
operation of each part of the GPIB-110.
• Appendix A, Hardware Specifications, lists the specifications of the GPIB-110.
• Appendix B, Multiline Interface Messages, lists the multiline interface messages and
describes the mnemonics and messages that correspond to the interface functions. These
functions include initializing the bus, addressing and unaddressing devices, and setting
device modes for local or remote programming. The multiline interface messages are
IEEE 488-defined commands that are sent and received with ATN TRUE.
• Appendix C, Operation of the GPIB, describes some basic concepts you should understand to
operate the GPIB. It also contains a description of the physical and electrical characteristics
as well as configuration requirements of the GPIB.
• Appendix D, Customer Communication, contains forms you can use to request help from
National Instruments or to comment on our products and manuals.
• The Glossary contains an alphabetical list and description of terms used in this manual,
including abbreviations, acronyms, metric prefixes, mnemonics, and symbols.
• The Index contains an alphabetical list of key terms and topics in this manual, including the
page where you can find each one.

About This Manual
GPIB-110 User Manual x © National Instruments Corporation
Conventions Used in This Manual
The following conventions are used in this manual:
italic Italic text denotes emphasis, a cross reference, or an introduction to a key
concept.
bold italic Bold italic text denotes a note, caution, or warning.
monospace Text in this font denotes sections of code and names of functions.
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms are listed in the
Glossary.
Related Documentation
The following manual contains information that may be helpful as you read this manual:
ANSI/IEEE Standard 488.1-1987, IEEE Standard Digital Interface for Programmable
Instrumentation
Customer Communication
National Instruments wants to receive your comments on our products and manuals. We are
interested in the applications you develop with our products, and we want to help if you have
problems with them. To make it easy for you to contact us, this manual contains comment and
configuration forms for you to complete. These forms are in Appendix D, Customer
Communication, at the end of this manual.

© National Instruments Corporation 1-1 GPIB-110 User Manual
Chapter 1
Description of the GPIB-110
This chapter contains general information about the National Instruments GPIB-110, lists the
contents of the GPIB-110 kit, and explains how to unpack the GPIB-110 kit.
The GPIB-110 is a high-performance bus extender with the following features:
•Transparent to user software
•Extends the distance between GPIB instruments up to 2 km
•Transfer rates up to 144 kbytes/s
•Choice of fiber optic or coaxial cable
•Passes control over the GPIB
•FCC Class A (verified) noise emission
•Optional rack-mount hardware
The high-speed GPIB-110 Bus Extender, shown in Figure 1-1, is used in pairs with serial fiber
optic or coaxial cables to connect two separate GPIB or IEEE 488 bus systems in a functionally
transparent manner. While the two bus systems are physically separate, as shown in Figure 1-2,
devices operate as if located on the same bus, as shown in Figure 1-3.
Figure 1-1. The Model GPIB-110 Bus Extender
Art not available in PDF version of document.

Description of the GPIB-110 Chapter 1
GPIB-110 User Manual 1-2 © National Instruments Corporation
At short distances, the data transfer rate over the extension can exceed 144 kbytes/s. The transfer
rate degrades as the distance increases. There is no speed degradation for transfers between
devices on the same side of the extension. Because the GPIB-110 is a functionally transparent
extender, the same GPIB communications and control programs that operate with an unextended
system work unmodified with an extended system. When conducting a parallel poll, with an
extended system, minor modifications are necessary. These are explained in the section titled,
Parallel Poll Response (PPR) Modes, in Chapter 2 of this manual.
GPIB #2
GPIB-110
Fiber Optic or 
Coaxial Cable
GPIB #1 GPIB-110
Computer
(System Controller,
Talker, and Listener) Printer
(Listener) Multimeter
(Talker and Listener) Signal Generator
(Listener)
Unit Under Test
Figure 1-2. Typical GPIB-110 Extension System (Physical Configuration)
Computer
(System Controller,
Talker, and Listener) Printer
(Listener) Multimeter
(Talker and Listener) Signal Generator (Listener)
Unit Under Test
GPIB
Figure 1-3. Typical GPIB-110 Extension System (Logical Configuration)

Chapter 1 Description of the GPIB-110
© National Instruments Corporation 1-3 GPIB-110 User Manual
With the GPIB-110, you can overcome the two following configuration restrictions imposed by
ANSI/IEEE Standard 488-1987:
• Cable length limit of 20 m per contiguous bus or 2 m times the number of devices on the bus,
whichever is smaller.
• Electrical loading limit of 15 devices per contiguous bus.
Each GPIB-110 system extends the distance limit by 2 km and the loading limit to 30 devices
including the extenders. You can connect these point-to-point extender systems in series for
longer distances or in star patterns for additional loading.
What Your Kit Should Contain
Your GPIB-110 kit should contain the following components:
Kit Component Part Number
Model GPIB-110 Bus Extender
100-120 VAC:
Fiber Optic Version 776103-01
Coaxial Version 776103-02
Dual Fiber Optic and Coaxial Capability 776103-03
220-240 VAC:
Fiber Optic Version 776103-31
Coaxial Version 776103-32
Dual Fiber Optic & Coaxial Capability 776103-33
Power Cord:
U.S. standard 3-wire power cable 763000-01
GPIB-110 User Manual 320052-01

Description of the GPIB-110 Chapter 1
GPIB-110 User Manual 1-4 © National Instruments Corporation
Optional Equipment
You can call National Instruments to order the following optional equipment to go with your kit.
Equipment Part Number
Rack-Mount Kit:
Single Rack-Mount Kit 180304-01
Dual Rack-Mount Kit 180304-02
Transmission Cable*:
Type T3 – Fiber Optic Cable 178058-xxx
Type T4 – Coaxial Cable 178057-xxx
(xxx = length in meters)
Type X2 GPIB Cable:
1 m 763061-01
2 m 763061-02
4 m 763061-03
8 m 763061-04
*For plenum cables, contact National Instruments.
Unpacking
Follow these steps when unpacking your GPIB-110:
1. Verify that the pieces contained in the package you received match the kit parts list
given earlier in this chapter.
2. Before you operate the GPIB-110, inspect the shipping container and its contents for
damage. Keep the packaging 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.
3. The GPIB-110 is shipped from the factory with a 100 to 120 VAC or 220 to 240 VAC
power supply. Verify that the voltage on the power supply matches the voltage that is
supplied in your area.
Caution: Operating the GPIB-110 at any voltage other than the one specified could
damage the unit.

© National Instruments Corporation 2-1 GPIB-110 User Manual
Chapter 2
Configuration and Installation
This chapter contains instructions for configuring, installing, and verifying the operation of the
GPIB-110.
Users unfamiliar with the GPIB should first read Appendix C, Operation of the GPIB, to become
familiar with GPIB terminology and protocol before continuing with this chapter.
The GPIB-110 comes in the following three models:
• The 776103-01 (776103-31) model–Uses an optical fiber cable.
• The 776103-02 (776103-32) model–Uses a coaxial cable.
• The 776103-03 (776103-33) model–Uses either type of cable.
The GPIB-110 has several configurations depending on the type and length of cable used and
other operating conditions.
Grounding Configuration
A U.S. standard 3-wire power cable is provided with the GPIB-110. When connected to a power
source, this cable connects the equipment chassis to the power ground.
The GPIB-110 is shipped from the factory with the logic ground of the digital circuitry
connected to both the power and chassis ground and interfacing cable shields.
If it is necessary to isolate either of these grounds to prevent current loops between units,
disassemble the unit according to the following instructions.
Hazardous voltage inside. Remove power cord before opening unit.
Warning:
˘
!
1. Turn the power switch to OFF. This switch is located on the rear panel of the GPIB-110.
2. Disconnect the power cord from the power source and from the rear panel of the GPIB-110.
3. Remove the cover from the GPIB-110 by first removing the two screws located on each side
of the housing. Lift off the cover.
To isolate the interface cable shield from the chassis, power ground, and logic ground,
change the interface cable Shield Selection Jumper shown in Figure 2-1, letter c, to the
position labeled ISO.

Configuration and Installation Chapter 2
GPIB-110 User Manual 2-2 © National Instruments Corporation
To isolate the digital logic ground from the chassis and power ground, change the chassis
ground to Logic Ground Selection jumpers shown in Figure 2-1, letter a, to the position
labeled ISO.
4. Replace the cover. Be sure the aluminum side plates are in the proper place.
5. Replace the screws you removed in Step 3.
6. Reconnect the power cord.
R3
R4
R5
CX FO
C2RV1 U1 U2 U3 C5
J2
C1
R2
R1C60 C9
R6
C3
U4
U15 U16
C6 C7
C10
C8
U20
J4MIT J3 RCV
C61
R9
D9
U51
U52
U17 U18
D1 D2 D3
C21
U34
U35 U36
U37
C30
U53
U54U55U56
U57
R1
U73 U74
U75
U76 U77
U78
S1
J5
C42
U94
U95 U96 U97 U98 U99
C44
C36 C37
C45
R12
U116 U117 U118 U119
ISO SH
U115
75121
75122
ALS00
7406
ALS04
AS00 LS164
AS02
7406
LS393
26012601
AS74 AS74
ALS00
LS126
LS164
ALS04
ALS151
S196
AS74
3441
3448
ALS273
ALS00 ALS00
ALS02
ALS00
76160
ALS257
ALS273
ALS257
ALS74
ALS32 ALS08
LS19
ALS08
ALS11
ALS74
ALS02
ALS166
Fiber Optic/Coaxial
Selection Jumpers
Chassis Ground
to Logic Ground
Selection
a.
GPIB-110 Rear Panel
Top View
b.
Interface Cable 
Shield Selection 
Jumper
c.
ISO
Figure 2-1. Isolation Selection

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-3 GPIB-110 User Manual
The GPIB-110 Front and Rear Panels
In the following discussions, the terms local and remote refer to certain states of the two
GPIB-110 Bus Extenders. When one extender is in a local state, meaning that the state in
question originated on its side, the other extender is in the corresponding remote state. The three
states in question are the System Controller, Active Controller, and Source Handshake.
The GPIB-110 Front Panel
The GPIB-110 front panel is shown in Chapter 1, Figure 1-1. The front panel has nine Light
Emitting Diodes (LEDs). The PWR LED on the left side of the front panel lights up whenever
power is applied to the GPIB-110.
The Serial Communication LEDs are LINK and ERR (error). The GPIB-110 condenses the 16
IEEE 488 signals into data packets that are sent across the serial link and are converted back to
IEEE 488 signals by the remote GPIB-110. When lit, the LINK LED indicates that the remote
GPIB-110 is on and the extension is operating normally. The ERR LED flashes whenever a data
packet containing an error is received.
The System Controller, Active Controller, and Source Handshake each have two LEDs
indicating local (LOC) and remote (REM). If the System Controller LOC LED is lit, the
Interface Clear (IFC) or Remote Enable (REN) message has been detected on the local GPIB. If
the System Controller REM LED is lit, IFC or REN has been received from the remote unit. If
the Active Controller LOC LED is lit, the Attention (ATN) message has been detected on the
local GPIB. If the Active Controller REM LED is lit, ATN has been received from the remote
unit. If the Source Handshake LOC LED is lit, a Data Valid (DAV) message has been detected
on the local GPIB; that is, the Talker is on the local GPIB. If the REM LED lights up, DAV has
been received from the remote unit; that is, the Talker is on the remote side.

Configuration and Installation Chapter 2
GPIB-110 User Manual 2-4 © National Instruments Corporation
The GPIB-110 Rear Panel
The GPIB-110 rear panel is shown in Figure 2-2. The rear panel contains all the GPIB-110
connectors and switches.
Figure 2-2. Rear Panel
The rear panel shown is for the 776103-03 (776103-33) model, which supports both fiber optic
and coaxial cable.
For all models, the power switch is located on the upper right corner of the rear panel. The fuse
housing is located directly to the right of the power switch. The GPIB connector is located
directly below the power switch and is labeled GPIB. To the left of the GPIB connector (center
bottom of panel) is the configuration switch, which is labeled CONFIGURATION.
For the 776103-01 (776103-31) and 776103-03 (776103-33) models, an LED is located to the
left of the configuration switch. The LED labeled FO SIGNAL OK is lit when the signal quality
received over the fiber optic cable is good. To the left of the LED are the optical fiber
connectors labeled RCVR for receive and TRANS for transmitter.
For the 776103-02 and 776103-03 models, the coaxial cable connector is located on the left-most
bottom corner of the rear panel. The connector is labeled COAX.

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-5 GPIB-110 User Manual
GPIB-110 Setup
Configure the GPIB-110 units before installing them and running the cable between them. This
step makes configuration easier. The main configuration switch is used to select other operating
modes. This switch is located on the rear panel of the GPIB-110 and, in most cases, is the only
switch you need to set before installing the GPIB-110s. Be sure to power-off the GPIB-110
before changing any switches. Figure 2-3 shows the default settings of the configuration switch.
On
Off
312 45678910
CONFIGURATION
= position of switch handle
Figure 2-3. Configuration Switch
The GPIB-110 has a label on the bottom of the box with important information. This label
shows the ten configuration switches with their names. The bottom left corner of the label lists
the Fiber Optic Transmit power settings. For more information on setting these switches, refer to
the section titled Fiber Optic Transmit Power, later in this chapter. The bottom right corner of
the label lists the configuration switch settings for Switches 8 through 10 and the corresponding
Transmit Clock Values. For more information, refer to the section titles Transmit Clock, later in
this chapter. Figure 2-4 shows the label on the bottom of the GPIB-110.
CONFIGURATION
12345678910
O
N
COPYRIGHT 1985
F.O.
TRANSMIT
POWER
SELFTEST ON
IFC WAIT OFF
MASTER ON
LATCHED POLL OFF
TRANSMIT CLOCK
{
{
OFF OFF
ON ON
SW
10 NO.
9 8 TRANSMIT
CLOCK
0
0
0
0
1
1
1
1
1
1
0
0
0
0
1
1
1
0
1
0
0
1
0
1
7.8 KHz
31 KHz
125 KHz
500 KHz
1 MHz
2 MHz
5 MHz
10 MHz
0 = OFF 1 = ON
SW
1 NO. 2 3
F.O.
TRANSMIT
POWER
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
100%
87.5%
75%
62.5%
50%
37.5%
25%
12.5%
0 = OFF 1 = ON
Figure 2-4. GPIB-110 Label
Place the GPIB-110s in close proximity and connect the cable to be used to each unit.

Configuration and Installation Chapter 2
GPIB-110 User Manual 2-6 © National Instruments Corporation
Cable Selection
The GPIB-110 is shipped with either a coaxial or fiber optic cable and with the cable selection
jumper set according to the model number. However, if you have to change the type of cable
you are using, you must also change the jumper setting located on the inside of the GPIB-110 as
shown in Figure 2-5. (See Figure 2-1, letter b, for the location of this jumper.)
CX
FO
RCV XMIT
Figure 2-5. Internal Cable Selection Jumper (Shown for Coaxial Cable)
Use the following steps to change the setting of the cable selection jumper.
Hazardous voltage inside. Remove power cord before opening unit.Warning:
˘
!
1. Turn the power switch to OFF. This switch is located on the rear panel of the GPIB-110.
2. Disconnect the power cord from the power source and from the rear panel of the GPIB-110.
3. Remove the cover from the GPIB-110 by first removing the two screws located on each side
of the housing. Lift off the cover.
4. The Internal Cable Selection Jumper, shown in Figure 2-5, is located underneath the
transformer near the rear panel. (See Figure 2-1, letter b, for the exact location.) Using
needle-nosed pliers (right angle works best), place the two blue jumpers on the correct
setting. The position labeled FO is for fiber optic cable. The position labeled CX is for
coaxial cable.
5. Replace the cover. Be sure the aluminum side plates are in the proper place.
6. Replace the screws you removed in Step 3.
7. Reconnect the power cord.
Coaxial Cable Setup
The coaxial cable should be connected to the Coaxial BNC connector on the rear panel of the
GPIB-110. When using a coaxial cable, Switch 4 on the rear panel configuration switch must be
set to ON (Self-Test mode OFF), and Switches 5 through 10 must be configured as explained in
the following sections. Refer to Figure 2-3 for the default settings of the configuration switch
and Figure 2-4 for other possible configurations.

Chapter 2 Configuration and Installation
© National Instruments Corporation 2-7 GPIB-110 User Manual
Fiber Optic Cable Setup
The fiber optic cable comes with two SMA-style connectors on each end. One connector should
be marked T for transmit; the other should be marked R for receive. Connect the connector
marked T to the fiber optic connector marked TRANS on the GPIB-110 rear panel. Connect the
connector marked R to the fiber optic connector marked RCVR on the GPIB-110 rear panel.
The connectors are connected by pushing the cable connector gently into the rear panel
connector and screwing the cable connector onto the rear panel connector securely.
When a fiber optic cable is used, Switch 4 on the rear panel configuration switch must be set to
the ON (Self-Test mode OFF) position, and Switches 1 through 3 and 5 through 10 must be
configured as explained in the following sections. Refer to Figure 2-3 for the default settings
and to Figure 2-4 for configuration options for fiber optic cable setup.
Master Switch Setting
The operation of the GPIB-110 requires one of the connected pairs of GPIB-110s to be
configured as the master. The master GPIB-110 is the one that initiates communication between
the GPIB-110s. Either side can be the master. On one of the GPIB-110s, set Switch 6 to the ON
position. Set Switch 6 of the other GPIB-110 to the OFF position. The GPIB-110 with the
master switch set in the OFF position is master.
Note: The master switch settings are reversed from the markings that appear on the switch.
To set your GPIB-110 as master, you must set the switch in the OFF position.
Fiber Optic Transmit Power
The Fiber Optic Transmit Power settings apply only to the GPIB-110 models using fiber optic
cable.
The Fiber Optic Transmit Power is adjustable from 12.5 percent to 100 percent power.
Operating the fiber optic transmitter at a lower power decreases power dissipation in the
GPIB-110 and can extend the life of the optical transmitter. The transmit power setting depends
on the length of optical fiber cable used.
Switches 1, 2, and 3 are used to set the transmit power of the transmitter LED. Figure 2-3 shows
the default settings for each switch and Figure 2-4 shows the power settings for the configuration
switch settings.
You must determine which power setting to use when the GPIB-110s are connected with the
fiber optic cable. The following steps list how to determine the power setting:
1. Turn on both GPIB-110s.
2. Set the transmit power switches on one of the GPIB-110s to the lowest power setting
(Switches 1, 2, and 3 in the ON position) and observe the SIGNAL OK LED on the rear
panel of the other GPIB-110 unit.
3. Increase the transmit power by changing the switches until the SIGNAL OK LED lights up
on the other GPIB-110. Then increase the power setting by one.
4. Set the transmit power switches on the other GPIB-110 to the same configuration.