IBM 6400 series Maintenance Manual page 46

RS–232
Diagnostic
Port
Control
Panel
TTL
Diagnostic
Port
46
25 or 40 MHz
Figure 17. CMX Controller Board Block Diagram
Expansion
Port
RS–232/422
IEEE–1284
(Parallel)
Fault
Sensors
Paper
Feed
Ribbon
Shuttle
Platen
Hammer
Drive
Principles of Operation