CP6100 I/O Process Programming Manual

Introduction
functions supplied by the controllers were implemented in
microcode; each controller has its own set. Controllers would
also manage the electrical interfaces for lines; for example,
the asynchronous controller supported the RS-232 standard, as
well as current loop connection and an autodialer interface.
S5064-003
Processor B
I/O Process
Backup
Processor A
I/O Process
Primary
First
Generation
Controller
Primary Path
to Lines
Backup Path
to Lines
$LINE1 $LINE2 $LINE3 $LINE4
I/O Channel A
I/O Channel B
Port A Port B
Figure 1-3. First Generation Controller Fault-Tolerance
1-7