IBM System/32 Introduction And Maintenance Manual page 178

Half Line Space Operation
The half line space print feature permits indexing
of the printer one half space above or below the
normal print line. This spacing can be used to
superscript or subscript any of the characters on the
the print belt.
The half line space print feature supplies the
printer attachment with 8 carriage advance pulses
when only 4 carriage advance pulses are sent by the
printer to the carriage advance shift register.
During the half line space operation, when the first
carriage advance pulse is received by the half index
card, 5 short (64 Ils) carriage advance pulses are
generated from the 4 IlS clock and sent to the
printer attachment before the second carriage ad-
vance pulse is received from the printer. When the
second pulse is received from the printer, it is passed
unaltered to the printer attachment. This pulse
becomes the sixth carriage advance pulse to the
printer attachment and carriage go is dropped. The
deceleration function begins and the third and
fourth carriage advance pulses from the printer are
received by the printer attachment. These are the
seventh and eighth pulses in the carriage line posi-
tion counter (count to 8). Because the printer
attachment has received 8 pulses in the carriage
line position counter, the acceleration and decel-
eration timing of a full index is retained and forms
jam and carriage sync checking are performed.
Printer
Adapter
on
I/O
Board
4 JJsec Clock
Half Index Complete
Diagnostic Only
Carriage Rev
Adapter Rst
Carriage Adv
Carriage Go
(carriage oscillator)
4-88
1/2 Index
Feature
on
I/O
Board
Carriage Advance
Carriage
Carriage Advance
Carriage
A
Advance Shift
B
Digital Register
A
Control and
In
Inh Detent
Carriage B
Printer Drive