|Volume 10, Number 23 |
Hewlett Packard designed the original bus in the 1960's. It was later accepted as a standard in 1978 by IEEE/ANSI as IEEE-488. At the time, it was revolutionary, allowing many convenient applications. An IEEE-488 bus can be configured as a physical star, in-line (linear) or a combination of both.
|In-Line / Linear Configuration|
|Physical / Star Configuration|
As with many products in the electronics industry, there are a few different names for the same thing. GPIB (General Purpose Interface Bus), HPIB (Hewlett Packard Interface Bus), and IEEE-488 (Institute of Electrical and Electronics Engineers Standard 488) are all common names for this system. Despite its many names and early popularity, IEEE-488 eventually gave way to smaller, lighter, cheaper, and faster interfaces.
IEEE-488 interfaces are typically found in high end, expensive instruments as opposed to lower cost equipment that uses RS232 interfaces.
IEEE-488 Cable/Connector Characteristics
- Maximum data rate is 1 Mbps
- Maximum bus cable length is 20 meters
- Maximum number of devices on the bus is 15
Unlike other bus systems there is only one connector style - this causes much less confusion! The connector is a 24-position male to female piggy back that allows for easy daisy chaining with metric hardware (M3x0.6). The cable is 24 conductors with an 85 percent minimum braid shield coverage.
IEEE-488 Connector Specifications
The IEEE-488 GPIB connector utilizes
24 contacts in a parallel configuration.
IEEE-488 Cable Construction
- 24 conductors with twisted pairs
- Braid Shield with a minimum
- Centronics style 24 position male to female piggy back connectors allowing for easy daisy chaining
- Metric mating hardware,
M3.5 x 0.6
IEEE-488 Cable Assembly Options
L-com offers three different cable options to best satisfy customer needs and maximize value:
| ||MOLDED ||DELUXE ||PREMIUM |
|Backshell Detail||PVC molded backshell over internal steel shell enclosure||Die cast aluminum, nickel plated backshell||Die cast aluminum, nickel plated backshell|
|Connector Detail||Stamped steel, nickel plated connectors||Die cast alloy, nickel plated connectors||Die cast alloy, nickel plated connectors|
|Contact Plating||30 microinch gold plated contacts||30 microinch gold plated contacts||30 microinch gold plated contacts|
|Cable Shielding||One braid and one foil/mylar overall shield||One braid and one foil/mylar overall shield plus one inner foil/mylar shield||One braid and one foil/mylar overall shield plus one inner braid and one inner foil/mylar shield|
What Can L-com Do For You?
L-com has designed and manufactures one of the largest IEEE-488 product offerings in the world!