The United States Air Force, and later Hewlett-Packard, recognized this as a problem. Commands to control the same class of instrument, e.g., multimeters, varied between manufacturers and even models.
While IEEE 488.1 defined the hardware and IEEE 488.2 defined the protocol, there was still no standard for instrument-specific commands. IEEE 488.2 built on IEEE 488.1 without superseding it equipment can conform to IEEE 488.1 without following IEEE 488.2. IEEE 488.2 provided for basic syntax and format conventions, as well as device-independent commands, data structures, error protocols, and the like. In 1987, IEEE introduced Standard Codes, Formats, Protocols, and Common Commands, IEEE 488.2. These standards formalized the mechanical, electrical, and basic protocol parameters of GPIB, but said nothing about the format of commands or data. The standard was revised in 1987, and redesignated as IEEE 488.1 (IEEE 488.1-1987). In 1975, the IEEE standardized the bus as Standard Digital Interface for Programmable Instrumentation, IEEE 488 it was revised in 1978 (producing IEEE 488-1978). As GPIB became popular, it was formalized by various standards organizations. It became known as the General Purpose Interface Bus (GPIB), and became a de facto standard for automated and industrial instrument control. HP licensed the HP-IB patents for a nominal fee to other manufacturers. For example, the HP 59501 Power Supply Programmer and HP 59306A Relay Actuator were both relatively simple HP-IB peripherals implemented in TTL, without the need for a microprocessor. The bus was relatively easy to implement using the technology at the time, using a simple parallel bus and several individual control lines.
They developed the HP Interface Bus (HP-IB) to enable easier interconnection between instruments and controllers (computers and other instruments). In the late 1960s, Hewlett-Packard (HP) manufactured various automated test and measurement instruments, such as digital multimeters and logic analyzers. 7 Comparison with other interface standards.
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