View source for GPIB

{{short description|General Purpose Interface Bus (GPIB) specification}}
{{Infobox computer hardware bus
| name        = GPIB
| fullname    = {{Plain list|
* General Purpose Interface Bus
* Hewlett-Packard Interface Bus
}}
| logo        = 
| image       = 
| image_size  = 
| alt         = 
| caption     = 
| invent-date = 1972<ref>{{Cite web|url=https://www.hp9845.net/9845/tutorials/hpib/|title=The Hewlett-Packard Interface Bus (HP-IB)}}</ref>
| invent-name = 
| super-name  = 
| super-date  = 
| replaces    = 
| width       = 
| numdev      = 
| speed       = 8 Mbyte/s
| style       = p
| hotplug     = 
| external    = 
| website     = {{URL|https://standards.ieee.org/ieee/488.1/716/}}
}}
[[file:IEEE-488-Stecker2.jpg|thumb|IEEE 488 cable with stacking connectors]]

'''General Purpose Interface Bus''' ('''GPIB''') or '''Hewlett-Packard Interface Bus''' ('''HP-IB''') is a short-range digital communications [[8-bit]] [[parallel communication|parallel]] [[Multi-master bus|multi-master]] [[Interface (computing)|interface bus]] specification originally developed by [[Hewlett-Packard]] and standardized in '''IEEE 488.1-2003'''. It subsequently became the subject of several standards. Although the bus was originally created to connect together [[automated test equipment]], it also had some success as a [[peripheral bus]] for early [[microcomputer]]s, notably the [[Commodore PET]]. Newer standards have largely replaced IEEE 488 for computer use, but it is still used by test equipment.

== History ==
In the 1960s, [[Hewlett-Packard]] (HP) manufactured various automated test and measurement instruments, such as digital [[multimeter]]s and [[logic analyzer]]s. They developed the ''HP Interface Bus (HP-IB)'' to enable easier interconnection between instruments and controllers (computers and other instruments).<ref>{{cite journal |first=Gerald E. |last=Nelson |first2=David W. |last2=Ricci |title=A Practical Interface System for Electronic Instruments |journal=Hewlett-Packard Journal |volume=24 |issue=2 |pages=2–7 |date=October 1972 |url=http://hparchive.com/Journals/HPJ-1972-10.pdf |quote=Controllers: 3260A Marked Card Reader; [[HP 9800 series#Second generation|9820A]] Calculator (with 11144A Interface Kit) }}<br/>{{cite journal |first=Donald C. |last=Loughry |title=A Common Digital Interface for Programmable Instruments: The Evolution of a System |journal=Hewlett-Packard Journal |volume=24 |issue=2 |pages=8–11 |date=October 1972 |url=http://hparchive.com/Journals/HPJ-1972-10.pdf}}</ref> This part of HP was later (c. 1999) spun off as [[Agilent Technologies]], and in 2014 Agilent's test and measurement division was spun off as [[Keysight Technologies]].<ref>{{cite web |date=7 January 2014 |title=Agilent Technologies Reveals Name of Electronic Measurement Spin-Off Company |url=http://www.agilent.com/about/newsroom/presrel/2014/07jan-gp14001.html |access-date=19 December 2014 |publisher=Agilent|archive-url=https://web.archive.org/web/20191208020546/https://www.agilent.com/about/newsroom/presrel/2014/07jan-gp14001.html|archive-date=8 December 2019}}</ref><ref>{{cite web |title=Exhibit 99.1 |url=https://www.sec.gov/Archives/edgar/data/1601046/000104746914001833/a2218670zex-99_1.htm |website=www.sec.gov}}</ref>

The bus was relatively easy to implement using the technology at the time, using a simple parallel [[Bus (computing)|bus]] and several individual control lines. For example, the HP 59501 Power Supply Programmer and HP 59306A Relay Actuator were both relatively simple HP-IB peripherals implemented in [[Transistor–transistor logic|TTL]], without the need for a microprocessor.

HP licensed the HP-IB patents for a nominal fee to other manufacturers. It became known as the General Purpose Interface Bus (GPIB), and became a [[de facto standard]] for automated and industrial instrument control. As GPIB became popular, it was formalized by various [[standards organization]]s.

In 1975, the [[Institute of Electrical and Electronics Engineers|IEEE]] standardized the bus as ''Standard Digital Interface for Programmable Instrumentation'', IEEE 488; it was revised in 1978 (producing IEEE 488-1978).<ref>{{Citation |title=IEEE Standard Digital Interface for Programmable Instrumentation |publisher=[[Institute of Electrical and Electronics Engineers]] |year=1978 |id=ANSI/IEEE Std 488-1978 |isbn=978-1-5044-0366-5 |doi=10.1109/IEEESTD.1978.7425098}}<br>{{Citation |title=IEEE Standard Digital Interface for Programmable Instrumentation |publisher=[[Institute of Electrical and Electronics Engineers]] |year=1987 |id=ANSI/IEEE Std 488.1-1987 |isbn=0-471-62222-2 <!-- This is the ISBN on the document --> }}, p. iii</ref> The standard was revised in 1987, and redesignated as IEEE 488.1 (IEEE 488.1-1987). These standards formalized the mechanical, electrical, and basic protocol parameters of GPIB, but said nothing about the format of commands or data.

In 1987, IEEE introduced ''Standard Codes, Formats, Protocols, and Common Commands'', IEEE 488.2. It was revised in 1992.<ref>{{Citation |title=IEEE Standard Codes, Formats, Protocols, and Common Commands for Use With IEEE Std 488.1-1987, IEEE Standard Digital Interface for Programmable Instrumentation |publisher=[[Institute of Electrical and Electronics Engineers]] |year=1992 |id=IEEE Std 488.2-1992 |isbn=978-1-55937-238-1 }}</ref> IEEE 488.2 provided for basic syntax and format conventions, as well as device-independent commands, data structures, error protocols, and the like. IEEE 488.2 built on IEEE 488.1 without superseding it; equipment can conform to IEEE 488.1 without following IEEE 488.2.

While IEEE 488.1 defined the hardware and IEEE 488.2 defined the protocol, there was still no standard for instrument-specific commands. Commands to control the same class of instrument, ''e.g.'', multimeters, varied between manufacturers and even models.

The United States Air Force,<ref>Project Mate in 1985</ref> and later Hewlett-Packard, recognized this as a problem. In 1989, HP developed their Test Measurement Language (TML)<ref>{{cite web | title = GPIB 101, A Tutorial of the GPIB Bus | publisher = ICS Electronics | url = http://www.icselect.com/ab_note.html#anchor338658 | page=5, paragraph = SCPI Commands }}</ref> or Test and Measurement Systems Language (TMSL)<ref>{{cite web | title = Hewlett Packard Test & Measurement Catalog 1991 | publisher = hparchive.com | url = http://hparchive.com/Catalogs/HP-Catalog-1991.pdf | page=8, paragraph = SCPI }}</ref> which was the forerunner to [[Standard Commands for Programmable Instrumentation]] (SCPI), introduced as an industry standard in 1990.<ref>{{cite web | title = History of GPIB | publisher = National Instruments | url = http://zone.ni.com/devzone/cda/tut/p/id/3419 | quote = In 1990, the IEEE 488.2 specification included the Standard Commands for Programmable Instrumentation (SCPI) document. | access-date = 2010-02-06 }}</ref> SCPI added standard generic commands, and a series of instrument classes with corresponding class-specific commands. SCPI mandated the IEEE 488.2 syntax, but allowed other (non-IEEE 488.1) physical transports.

The [[International Electrotechnical Commission|IEC]] developed their own standards in parallel with the IEEE, with IEC 60625-1 and IEC 60625-2 (IEC 625), later replaced by [[IEC 60884|IEC 60488-2]].

[[National Instruments]] introduced a backward-compatible extension to IEEE 488.1, originally known as HS-488. It increased the maximum data rate to 8 [[megabyte|Mbyte]]/s, although the rate decreases as more devices are connected to the bus. This was incorporated into the standard in 2003 (IEEE 488.1-2003),<ref>{{Cite web | title = Upgraded Standard Boosts Speed of IEEE 488 Instrument Buses Eightfold | date = 2003-10-06 | publisher = IEEE | url = http://standards.ieee.org/announcements/pr_4881upgrade.html | archive-url = https://web.archive.org/web/20031207052849/http://standards.ieee.org/announcements/pr_4881upgrade.html | url-status = dead | archive-date = December 7, 2003 | access-date = 2010-02-06 }}</ref> over HP's objections.<ref>{{Cite press release|title=HP and Other Test and Measurement Companies Urge IEEE to Oppose Revisions of Established IEEE 488 Standard |publisher=Hewlett-Packard Company |date=December 1997 |url=http://grouper.ieee.org/groups/imstc8/488/1/hppress12-97.html |access-date=2010-02-16 |url-status=dead |archive-url=https://web.archive.org/web/20110610164221/http://grouper.ieee.org/groups/imstc8/488/1/hppress12-97.html |archive-date=2011-06-10}}</ref><ref>{{cite web|title=P488.1 Project Home |publisher=IEEE |url=http://grouper.ieee.org/groups/imstc8/488/1/ |access-date=2010-02-16 |url-status=dead |archive-url=https://web.archive.org/web/20100428090906/http://grouper.ieee.org/groups/imstc8/488/1/ |archive-date=2010-04-28}}</ref>

In 2004, the IEEE and IEC combined their respective standards into a "Dual Logo" IEEE/IEC standard IEC 60488-1, ''Standard for Higher Performance Protocol for the Standard Digital Interface for Programmable Instrumentation - Part 1: General'',<ref>{{cite book | title = IEC/IEEE Standard for Higher Performance Protocol for the Standard Digital Interface for Programmable Instrumentation - Part 1: General (Adoption of IEEE Std 488.1-2003) | publisher = IEEE | doi = 10.1109/IEEESTD.2004.95749 | isbn = 978-0-7381-4536-5 }}</ref> replaces IEEE 488.1/IEC 60625-1, and IEC 60488-2,''Part 2: Codes, Formats, Protocols and Common Commands'',<ref>{{cite book | title = Standard Digital Interface for Programmable Instrumentation- Part 2: Codes, Formats, Protocols and Common Commands (Adoption of (IEEE Std 488.2-1992) | publisher = IEEE | doi = 10.1109/IEEESTD.2004.95390 | hdl = 11059/14380 | isbn = 978-0-7381-4100-8 }}</ref> replaces IEEE 488.2/IEC 60625-2.<ref>{{cite web | title = Replaced or Withdrawn Publications | url = http://www.iec.ch/cgi-bin/procgi.pl/www/iecwww.p?header=IEC&search=replaced&wwwprog=sea22.p | publisher = IEC | access-date = 2010-02-06 | url-status = dead | archive-url = https://archive.today/20120417191411/http://www.iec.ch/cgi-bin/procgi.pl/www/iecwww.p?header=IEC&search=replaced&wwwprog=sea22.p | archive-date = 2012-04-17 }}</ref>

== Characteristics ==
IEEE 488 is an [[8-bit]], electrically [[parallel communication|parallel]] bus which employs sixteen signal lines — eight used for bi-directional data transfer, three for [[Handshake (computing)|handshake]], and five for bus management — plus eight ground return lines.

The bus supports 31 five-bit primary device addresses numbered from 0 to 30, allocating a unique address to each device on the bus.<ref name="NI-488.2">{{Cite book | title = NI-488.2 User Manual | date = February 2005 | publisher = National Instruments Corporation | id = NI P/N 370428C-01 | page = A-2 | chapter = GPIB Addressing | quote = The primary address is a number in the range 0 to 30. | chapter-url = http://www.ni.com/pdf/manuals/370428c.pdf | access-date = 2010-02-16 }}</ref><ref name="Agilent_82350B">{{Cite book|chapter-url=http://literature.cdn.keysight.com/litweb/pdf/82350-90004.pdf|title=Agilent 82350B PCI GPIB Interface: Installation and Configuration Guide|date=2009-07-20|publisher=Agilent Technologies|page=26|chapter=Table 1-1: 82350 GPIB interface card configuration parameters|id=Agilent P/N 82350-90004|quote=any address in the range 0 - 30, inclusive, may be used|access-date=2010-02-16}}</ref>

The standard allows up to 15 devices to share a single physical bus of up to {{convert|20|m}} total cable length. The physical topology can be linear or star (forked).<ref>{{Cite web | title = GPIB Instrument Control Tutorial | publisher = National Instruments | date = 2009-08-24 | quote = connected in either a daisy-chain or star topology | url = http://zone.ni.com/devzone/cda/tut/p/id/2761 | access-date = 2010-02-16 }}</ref> Active extenders allow longer buses, with up to 31 devices theoretically possible on a logical bus.

Control and data transfer functions are logically separated; a controller can address one device as a "talker" and one or more devices as "listeners" without having to participate in the data transfer. It is possible for multiple controllers to share the same bus, but only one can be the "Controller In Charge" at a time.<ref>{{Cite book | title = NI-488.2 User Manual | date = February 2005 | publisher = National Instruments Corporation | id = NI P/N 370428C-01 | page = A-1 | url = http://www.ni.com/pdf/manuals/370428c.pdf | access-date = 2010-02-16 | archive-url = https://web.archive.org/web/20081202204121/http://www.ni.com/pdf/manuals/370428c.pdf | archive-date = 2008-12-02 | url-status = dead }}</ref>

In the original protocol, transfers use an interlocked, three-wire ''ready–valid–accepted'' handshake.<ref>{{Cite book | title = NI-488.2 User Manual | date = February 2005 | publisher = National Instruments Corporation | id = NI P/N 370428C-01 | page = A-3 | chapter = Handshake Lines | chapter-url = http://www.ni.com/pdf/manuals/370428c.pdf | access-date = 2010-02-16 }}</ref> The maximum data rate is about one megabyte per second. The later HS-488 extension relaxes the handshake requirements, allowing up to 8 Mbyte/s. The slowest participating device determines the speed of the bus.<ref>{{Cite web | title = Using HS488 to Improve GPIB System Performance | publisher = National Instruments Corporation | date = 30 March 2009 | url = http://zone.ni.com/devzone/cda/tut/p/id/4552 | access-date = 2010-02-16 }}</ref>

== Connectors ==
{{ infobox connector
| name           = IEEE 488
| pinout_image   = [[file:IEEE-448.svg|300px]]
| pinout_caption = Female IEEE 488 connector
| pin1  = Data input/output bit    | pin1_name  = DIO1
| pin2  = Data input/output bit    | pin2_name  = DIO2
| pin3  = Data input/output bit    | pin3_name  = DIO3
| pin4  = Data input/output bit    | pin4_name  = DIO4
| pin5  = End-or-identify          | pin5_name  = EOI
| pin6  = Data valid               | pin6_name  = DAV
| pin7  = Not ready for data       | pin7_name  = NRFD
| pin8  = Not data accepted        | pin8_name  = NDAC
| pin9  = Interface clear          | pin9_name  = IFC
| pin10 = Service request          | pin10_name = SRQ
| pin11 = Attention                | pin11_name = ATN
| pin12 =                          | pin12_name = SHIELD
| pin13 = Data input/output bit    | pin13_name = DIO5
| pin14 = Data input/output bit    | pin14_name = DIO6
| pin15 = Data input/output bit    | pin15_name = DIO7
| pin16 = Data input/output bit    | pin16_name = DIO8
| pin17 = Remote enable            | pin17_name = REN
| pin18 = (wire twisted with DAV)  | pin18_name = GND
| pin19 = (wire twisted with NRFD) | pin19_name = GND
| pin20 = (wire twisted with NDAC) | pin20_name = GND
| pin21 = (wire twisted with IFC)  | pin21_name = GND
| pin22 = (wire twisted with SRQ)  | pin22_name = GND
| pin23 = (wire twisted with ATN)  | pin23_name = GND
| pin24 =                          | pin24_name = Logic ground
}}

IEEE 488 specifies a 24-pin [[Amphenol]]-designed [[micro ribbon]] connector. Micro ribbon connectors have a D-shaped metal shell, but are larger than [[D-subminiature]] connectors. They are sometimes called "Centronics connectors" after the [[IEEE 1284|36-pin micro ribbon]] connector [[Centronics]] used for their printers.

One unusual feature of IEEE 488 connectors is they commonly use a "double-headed" design, with male on one side, and female on the other. This allows stacking connectors for easy [[daisy chain (electrical engineering)|daisy-chaining]]. Mechanical considerations limit the number of stacked connectors to four or fewer, although a workaround involving physically supporting the connectors may be able to get around this.

They are held in place by screws, either 6-32 UNK<ref>{{Cite book|chapter-url=http://bitsavers.org/pdf/hp/hpib/TutorialDescrOfHPIB.pdf |title=Tutorial Description of the Hewlett-Packard Interface Bus |publisher=Hewlett-Packard|page=28|chapter=Mechanical Aspects|quote=Some existing cables use English threads (6-32UNK).|access-date=2022-06-13}}</ref> (now largely obsolete) or [[ISO metric screw thread|metric]] M3.5×0.6 [[screw thread|thread]]s. Early versions of the standard suggested that metric screws should be blackened to avoid confusion with the incompatible UTS threads. However, by the 1987 revision this was no longer considered necessary because of the prevalence of metric threads.<ref>{{Citation |title=IEEE Standard Digital Interface for Programmable Instrumentation |publisher=[[Institute of Electrical and Electronics Engineers]] |year=1987 |id=ANSI/IEEE Std 488.1-1987 |isbn=978-0-471-62222-2|page=v|quote=The "helpful note" on metric threads found in previous editions has been deleted since metric thread use is common IEEE 488 practice. Consequently, the recommendation to coat such parts in black material to call attention to metric threads is also considered unnecessary.}}</ref>

The IEC 60625 standard prescribes the use of 25-pin [[D-subminiature]] connectors (the same as used for the [[parallel port]] on [[IBM PC compatible]]s). This connector did not gain significant market acceptance against the established 24-pin connector.

== Capabilities ==
[[file:IEEE-488 port with listed capabilities on a laboratory temperature controller.jpg|thumb|IEEE-488 port with listed capabilities on a laboratory temperature controller]]

{| class="wikitable"
|+ Capabilities<ref>{{Citation |last=Tilden |first=Mark D. |title=4041 GPIB Programming Guide |year=1983 |chapter=Appendix A: Subsets Describe Interface Functions |pages= 113&ndash;115 |publisher=Tektronix, Inc. |chapter-url=http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/tektronix/404x/070-4696-00_4041_GPIB_Programming_Guide_Sep1983.pdf }}</ref>
|-
! Function
! colspan=2 | Abbreviation
! Description and examples
|-
| Source Handshake
| SH
| 1
| Complete
|-
| Acceptor Handshake|| AH
| 1
| Complete
|-
| rowspan=3 | Basic Talker
| rowspan=3 | T 
| 5
| Responds to serial poll; untalks when listen address received; talk only capability
|-
| 6
| Untalks when listen address received; no talk only
|-
| 7
| No serial poll; untalks when listen address received; talk only capability
|-
| Extended Talker
| TE
| 0
| No extended talker
|-
| rowspan=2 | Basic Listener
| rowspan=2 | L
| 3
| Listen only mode; unlistens if talk address received
|-
| 4
| Unlistens if talk address received
|-
| Extended Listener
| LE
| 0
| No extended listener
|-
| rowspan=2 | Service Request
| rowspan=2 | SR
| 0
| No service request capability
|-
| 1
| Complete
|-
| rowspan=2 | Remote-Local
| rowspan=2 | RL
| 0
| No local lockout
|-
| 1
| Complete
|-
| Parallel Poll
| PP
| 0
| Does not respond to Parallel Poll
|-
| Device Clear
| DC
| 1
| complete
|-
| rowspan=2 | Device Trigger
| rowspan=2 | DT
| 0
| No device trigger capability
|-
| 1
| Complete
|-
| Controller
| C
| 0
| No controller function
|-
| rowspan=2 |
| rowspan=2 | E
| 1
| Open collector drive electronics
|-
| 2
| Three state drivers
|}

== Use as a computer interface ==
[[File:National pci GPIB card IMGP1642 smial wp.jpg|thumb|[[National Instruments]] GPIB controller card for [[Peripheral Component Interconnect|PCI]] bus]]

HP's designers did not specifically plan for IEEE 488 to be a peripheral interface for general-purpose computers; the focus was on instrumentation. But when HP's early [[microcomputer]]s needed an interface for peripherals ([[disk drive]]s, [[tape drive]]s, [[computer printer|printers]], [[plotter]]s, etc.), HP-IB was readily available and easily adapted to the purpose.

HP computer products which used HP-IB included the [[HP Series 80]], [[HP 9800 series]],<ref>{{cite web | title = HP 98135A HP-IB Interface 9815 | url=http://www.hpmuseum.net/display_item.php?hw=463 | work = HP Computer Museum | access-date = 2010-02-06 }}</ref> the [[HP 2100]] series,<ref>{{cite web | title = 59310A HP-IB Interface | quote = HP-IB interface for HP1000 and HP2000 computers | url=http://www.hpmuseum.net/display_item.php?hw=522 | work = HP Computer Museum | access-date = 2010-02-06 }}</ref> and the [[HP 3000]] series.<ref>{{cite web | title = 27113A HP-IB Interface | quote = CIO HP-IB interface for 3000 Series 900 | url=http://www.hpmuseum.net/display_item.php?hw=786 | work = HP Computer Museum | access-date = 2010-02-06 }}</ref> HP computer peripherals which did not utilize the RS-232 communication interface often used HP-IB including disc systems like the [[HP 7935]]. Some of HP's advanced pocket calculators of the 1980s, such as the [[HP-41]] and [[HP-71B]] series, also had IEEE 488 capabilities, via an optional [[HP-IL]]/HP-IB interface module.

Other manufacturers adopted GPIB for their computers as well, such as with the [[Tektronix 405x]] line.

The [[Commodore PET]] (introduced 1977) range of personal computers connected their peripherals using the IEEE 488 bus, but with a non-standard card edge connector. Commodore's following 8-bit machines utilized a [[Commodore bus|serial bus]] whose protocol was based on IEEE 488.<ref>{{cite book |last=Bagnall |first=Brian |date=2006 |title=On the Edge: The Spectacular Rise and Fall of Commodore |publisher=Variant Press |page=221 |isbn=0-9738649-0-7 |oclc=761384138 }}</ref> Commodore marketed an IEEE 488 cartridge for the VIC-20<ref>Commodore drawing for VIC-1112 - Drawing no. 1110010 Rev:A</ref> and the Commodore 64.<ref>[http://www.zimmers.net/anonftp/pub/cbm/schematics/cartridges/c64/ieee-488/index.html Reverse-engineered schematics for Commodore C64 IEEE interface]</ref> Several third party suppliers of [[Commodore 64 peripherals]] made a cartridge for the C64 that provided an IEEE 488-derived interface on a card edge connector similar to that of the PET series.<ref>http://www.zimmers.net/anonftp/pub/cbm/schematics/cartridges/c64/ieee-488/index.html Link to schematic for one such converter.</ref>

Eventually, faster, more complete standards such as [[SCSI]] superseded IEEE 488 for peripheral access.

<gallery widths=160 heights=90>
Commodore 8032-SK -- rear panel.jpg|Rear of [[Commodore PET|Commodore 8032-SK]] showing IEEE&nbsp;488 port
SFD1001 back.jpg|Rear of [[Commodore International|Commodore]] SFD 1001 [[floppy disk drive]] with IEEE&nbsp;488 port
Technofor-IEEE488.JPG|C64 interface
Acorn IEEE488 Interface (back).jpg|[[Acorn Computers|Acorn]] IEEE&nbsp;488 Interface
USB-GPIB-Converter.jpg|[[USB]] GPIB [[Protocol converter]]
Digitaloszilloskop Schnittstellen IMGP1974 WP.jpg|Rear of [[Tektronix]] TDS 210 digital [[oscilloscope]] with IEEE&nbsp;488 port
Data Acquisition Agilent %282%29.jpg|Rear of [[Keysight]] 34970A [[data acquisition]] chassis / [[multimeter]] with IEEE&nbsp;488 port
Keithley DMM7510 7.5 Digit Bench Multimeter (16895247108).jpg|Rear of [[Keithley Instruments|Keithley]] DMM7510 [[multimeter]] with IEEE&nbsp;488 port
7580B Plotter Settings.jpg|[[Hewlett-Packard|HP]] 7580B [[plotter]] with IEEE 488 port
Hp-thinkjet-a-rear.jpg| HP [[ThinkJet]] 2225A with IEEE 488 port
</gallery>

== Comparison with other interface standards ==
{{Unreferenced section|date=February 2010}}

Electrically, IEEE 488 used a hardware interface that could be implemented with some discrete logic or with a microcontroller. The hardware interface enabled devices made by different manufacturers to communicate with a single host. Since each device generated the asynchronous handshaking signals required by the bus protocol, slow and fast devices could be mixed on one bus. The data transfer is relatively slow, so [[transmission line]] issues such as impedance matching and line termination are ignored. There was no requirement for [[galvanic isolation]] between the bus and devices, which created the possibility of [[Ground loop (electricity)|ground loops]] causing extra noise and loss of data.

Physically, the IEEE 488 connectors and cabling were rugged and held in place by screws. While physically large and sturdy connectors were an advantage in industrial or laboratory set ups, the size and cost of the connectors was a liability in applications such as personal computers.

Although the electrical and physical interfaces were well defined, there was not an initial standard command set. Devices from different manufacturers might use different commands for the same function.<ref>Early devices might respond to an <code>ID</code> command with an identification string; later standards had devices respond to the <code>*ID</code> command.</ref> Some aspects of the command protocol standards were not standardized until [[Standard Commands for Programmable Instruments]] (SCPI) in 1990. Implementation options (e.g. end of transmission handling) can complicate interoperability in pre-IEEE 488.2 devices.

More recent standards such as [[USB]], [[FireWire]], and [[Ethernet]] take advantage of declining costs of interface electronics to implement more complex standards providing higher bandwidth. The multi-conductor (parallel data) connectors and shielded cable were inherently more costly than the connectors and cabling that could be used with serial data transfer standards such as [[RS-232]], [[RS-485]], USB, FireWire or Ethernet. Very few mass-market personal computers or peripherals (such as printers or scanners) implemented IEEE 488.

== See also ==
{{commonscat}}
* {{annotated link|Commodore bus}}
* {{annotated link|HP Series 80}}
* {{annotated link|HP-IL}}
* {{annotated link|LAN eXtensions for Instrumentation}}
* {{annotated link|PCI eXtensions for Instrumentation}}
* {{annotated link|Rocky Mountain BASIC}}
* {{annotated link|Standard Commands for Programmable Instruments}}
* {{annotated link|Virtual Instrument Software Architecture}}

== References ==
{{Reflist}}

== External links ==
;Part 1 Specifications
* [https://ieeexplore.ieee.org/document/1405845 IEEE/IEC 60488-1-2004], 158 page PDF file, costs [https://store.accuristech.com/standards/ieee-iec-60488-1-2004?product_id=1779369 USD$407] in 2025

;Part 2 Specifications
* [https://ieeexplore.ieee.org/document/8705775 IEEE 488.2-1992], 254 page PDF file, costs [https://www.techstreet.com/ieee/standards/ieee-488-2-1992?product_id=1888634 USD$54] in 2025 ''(superseded by IEEE/IEC 60488-2-2004)''
* [https://ieeexplore.ieee.org/document/1352831 IEEE/IEC 60488-2-2004], 264 page PDF file, costs [https://www.techstreet.com/ieee/standards/ieee-iec-60488-2-2004?product_id=1779348 USD$388] in 2025

;Other
* [https://www.electronics-notes.com/articles/test-methods/gpib-ieee-488-bus/what-is-gpib-ieee488.php GPIB / IEEE 488 multiple page tutorial]

{{Computer-bus}}
{{Hewlett-Packard}}
{{IEEE standards}}
{{Authority control}}

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[[Category:IEEE standards]]
[[Category:Electronic test equipment]]