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IEEE-488 GPIB Tutorial

What are GPIB cables? How are GPIB cables used? Where are GPIB cables used?
GPIB cables consist of 12 twisted pairs of copper They are used in a bus or star architecture where GPIB cables are typically used in test and
wire and utilize a Centronics 24 style male/female the connectors "piggy back" each other and then measurement applications and are also used in
connector. connect primarily test and measurement DAQ (data acquisition) applications.
equipment to PCs and other devices.

IEEE-488 Cabling Terms Connector: Electromechanical coupling device that Insulation: A material with very high resistivity used
Adapter: A device used to interconnect two different provides an electrical interface that can be mated and to protect conductors. Insulation is usually extruded
over the wire or conductor after the drawing process.
unmated.
connector types.
Contact: The specific points of contact within a Insulation Displacement Contact: A means of
American Wire Gauge (AWG): A U.S. standard set of connector. Contacts can be male (pins) or female terminating wires without the need of stripping down
non-ferrous wire conductor sizes. Typical data wiring (sockets). to the bare wire.
is AWG number 24, 26 or 28. The higher the gauge
number, the smaller the diameter and thinner the Coupler: A device used to connect two similar Jack: The female receptacle - usually found on
wire. connector types. equipment.
Backshell (Hood): A mechanical backing that is Crosstalk: The coupling of electromagnetic fields Plug: Popular term for a male gender connector of
sometimes put onto a connector. The device protects from conductors into adjacent conductors. Crosstalk varied types.
the conductors and can be assembled or injection is controlled by twisting the conductors into a pair or Shielding: A conductive foil or braid that covers
molded. by separating/shielding conductors. insulated wires in a cable. The shield provides
Bus: Also called a "Daisy Chain". A network topology Electromagnetic Interference (EMI): Unwanted electrical grounding and protection from external
where each node is connected to one another in line. electromagnetic or electrical energy that causes electromagnetic interference (EMI). Shielding is also
A major disadvantage is that when there is a break in unwanted responses in electronic equipment. used to control internal electromagnetic radiation.
the bus the entire network goes down. GPIB: General Purpose Interface Bus. Common name Strain Relief: A method of protecting the wire to
Cable: A set of insulated wires or conductors within for IEEE-488. contact point from flexing or pulling.
an extruded jacket. Many types of cable utilize HPIB: Hewlett Packard Interface Bus. Common name Twisted Pair: Two insulated conductors twisted at a
shielding around the wires and under the cable jacket. for IEEE-488. fixed rate of twists per unit of length, typically used in
Cable Assembly: A piece of cable that has been IEEE-488: Institute of Electrical and Electronics balanced circuits where nominal impedance and
terminated with one or more connectors. Engineers interface standard number 488. crosstalk are critical characteristics.
Conductor: A metal path, usually copper, that passes Injection Molding: The process used to inject molten Wire: Conductive material, typically copper, that has
electricity. When discussing data cabling, "wire" and polymer into a mold. Connector backshells are often been drawn down to a specific size and coated with
"conductor" are synonymous. injection molded. an insulating material. A "bare wire" utilizes no
insulator coating.

In-Line/Linear Configuration Physical/Star
Printer Plotter Scanner Configuration

IEEE-488 Connector Jack
Specifications
The IEEE-488 GPIB connector utilizes
24 contacts in a parallel configuration.
Printer
Plotter Printer Scanner
Plug
IEEE-488 Construction
PLUG (male) JACK (female) • 24 conductors with twisted pairs
• Braid Shield with a minimum 85% coverage
• Centronics style 24 position male to female
piggy back connectors allowing for easy
daisy chaining
Pin 1 Pin 24 Pin 24 Pin 1 • Metric mating hardware, M3.5 x 0.6

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