The Keysight/Agilent/HP 27209 is an ISA bus interface card that enables computer control and communication with GPIB instruments. This memory-mapped I/O card implements the HP-IB (Hewlett-Packard Interface Bus) standard, later formalized as IEEE-488, providing a bridge between legacy test equipment and computer systems. Originally introduced in the mid-1980s, the 27209 served as the foundation for GPIB connectivity before successor models like the HP 82335 emerged.
## Technical Specifications
• **Bus Interface:** ISA (Industry Standard Architecture) expansion slot
• **GPIB Standard:** HP-IB / IEEE-488 compliant
• **Maximum Bus Devices:** Up to 15 instruments per single GPIB bus
• **Maximum Bus Length:** 20 meters total
• **Memory Architecture:** Memory-mapped I/O
## Key Features
• Direct ISA slot installation for host computer integration
• Multi-device instrument control on single GPIB channel
• IEEE-488 standardized protocol implementation
• Legacy platform support for DOS and Windows 3.x environments
## Typical Applications
• Automated test equipment (ATE) systems using vintage GPIB instruments
• Laboratory measurement and control in DOS/early Windows environments
• Instrument interconnection for distributed measurement networks
• Educational and research facilities operating legacy test benches
## Compatibility & Integration
The 27209 interfaces with any GPIB/IEEE-488 compliant instrument. Direct compatibility exists with DOS and Windows 3.x operating systems. The HP 82335 card provides functional compatibility as a successor platform with minor enhancements. ISA bus architecture limits deployment to systems with available ISA expansion slots—increasingly rare in modern computing platforms. As a legacy product, the 27209 is end-of-life from the manufacturer; third-party suppliers may provide availability and support for existing installations.
