Theory of Operation
Chapter 4
GPIB-140 User Manual
4-2
© National Instruments Corp.
Message Interpreter
Layer
Message Interpreter
Layer
Packet Translation
Layer
Packet Translation
Layer
Link Management
Layer
Link Management
Layer
Parallel-to-Serial
Conversion Layer
Physical Layer
GPIB BUS #2
GPIB BUS #1
GPIB EXTENDER
GPIB EXTENDER
Transmission
Medium
Parallel-to-Serial
Conversion Layer
Physical Layer
Figure 4-1. GPIB Extender Block Diagram
Message Interpreter Layer
The Message Interpreter Layer handles the handshake between the GPIB extender and
other devices on the GPIB. At the same time, it monitors the activities occurring on the
GPIB and translates them into equivalent GPIB local and remote messages. These
messages are sent to the Packet Translation Layer.
