IEEE 488
A versatile bus system is standardized under IEEE 488, which is mainly used in electronic measurement technology as a bus system between measuring instruments. IEEE 488 corresponds to the General Purpose Interface Bus( GPIB), which was standardized in the 1970s under the designation IEEE 488. Like the GPIB bus, IEEE 488 uses a handshake method and can daisy-chain up to 31 peripheral devices.
The IEEE 488 bus consists of 5 control lines, 3 handshake lines, 8 data lines and various ground/shield lines. Communication is between the three components: Controller, Talker and Listener, where different devices can perform multiple functions simultaneously. Thus, a controller can also be a talker or listener, and a talker can also be a listener.
As a command language, IEEE 488 uses the general purpose Standard Commands for Programmable Instruments( SCPI), which is standardized as part of IEEE 488. The version IEEE 488.1 from the 70s supports the transmission of remote messages, in the improved version 488.2 the syntax and the data structures as well as the general commands and request commands for GPIB are specified. So also commands for status reports, error handling and controller functions. And with SCPI the specific command sets for the individual measuring devices are specified.