NI GPIB-140A 186135H-01L Fiber Optic GPIB Extender

The National Instruments GPIB-140A (part number 186135H-01L) is a high-speed fiber-optic bus extender designed to overcome the physical limitations of standard GPIB cabling. It extends the maximum GPIB cable length from 20 meters to 1 kilometer (3.2 km when paired with a second extender) and expands the maximum number of GPIB devices from 15 to 26, all without any software modifications to existing systems.

GPIB Extension Technology

The GPIB-140A uses buffered transfer techniques to convert parallel GPIB signals into serial fiber-optic data streams, then reconstructs them at the receiving end. This conversion is completely transparent to software and connected instruments, requiring no changes to existing GPIB applications or drivers. The extender supports both IEEE 488.1 and HS488 (high-speed) protocols, automatically negotiating the maximum possible data rate. For distances up to 2 kilometers, two GPIB-140A units can be paired using GPIB Type T8 fiber-optic cable.

Device Capacity Expansion

Standard GPIB systems are limited to 15 devices (including the controller) due to electrical loading constraints. The GPIB-140A overcomes this limitation by electrically isolating each segment of the GPIB bus, allowing up to 26 devices to be connected in a single system. The extender also provides electrical isolation between GPIB segments, preventing ground loops and protecting equipment from voltage surges.

Application Domains

The GPIB-140A is used in semiconductor manufacturing for long-distance test equipment placement, research laboratories for distributed instrument control, aerospace and defense for remote monitoring of test systems, and industrial automation for extending GPIB networks across large facilities. It is also used to connect GPIB instruments in hazardous areas to a safe control room.