HP 8340B Manual page 272

A5 KEYBOARD ASSEMBLY AND A7 LOWER KEYBOARD ASSEMBLY
The A5 keyboard and the A7 lower keyboard assemblies provide the mechanical mounting
for all instrument key
assemblies. The key annunciators are
also located on these
assemblies. The keyboard assemblies communi¬
cate with the instrument microprocessor via the A6 keyboard interface assembly.
A6 KEYBOARD INTERFACE ASSEMBLY
The A6 keyboard interface assembly provides
the communications link between the
instrument microprocessor,
the front
panel rotary
pulse generator (RPG), and A5 and A7 keyboards. The
interface contains all
data buffers,
annunciator latches, and interrupt circuitry to monitor the front panel keyboards and annunciators. RPG control
circuitry
(counters/timers) and the instrument preset circuitry are also located on the
A6 assembly.
G-4
Front Panel
Theory of Operation HP 8340B/41B