HP 7470A Interfacing And Programming Manual page 149

On-Line, Programmed-On State
When the rear—panelswitch labeled Y/D is set to D,the plotter is placed
in the on-line, programmed-on state by turning on the plotter. When the
Y/D switch is set to Y, the plotter is switched from the on—line,
programmed-off state to the on—line, p rogrammed-on state when a
plotter on instruction, ESC . ( or ESC . Y, is received from the computer.
When in this state, the plotter operates in response to instructions
received from the computer as shown in the following figure. When the
plotter instructions request output, it is provided as shown. The commu­
nication channel from the terminal to the computer, through the
plotter, is maintained to provide operator entry into the computer.
The plotter's processor monitors the channel from the terminal to the
computer for a terminal—generatedBreak signal. The plotter will inter­
pret anything greater than a 130-millisecond space as a Break. This a
Break signal is retransmitted to the computer and in—process plotter
outputs are aborted, but plotting continues until stored buffer data is
completed. A new plotter on instruction from the computer is required
to resume plotting operations. The plotter will ignore a Break signal if
the Y/D switch is set to D.
It should be noted that in the on-line, programmed—onstate (but not in
monitor mode which is described in the next paragraph) all data
generated by the terminal are routed through to the computer on a
noninterference basis when the plotter is not doing outputs. Data
generated by the terminal are ignored while output is occurring. How­
ever, all data generated by the computer are intercepted by the plotter
and not passed to the terminal.
COMPUTER
TERMINAL
1 PLOTTER V. | \
LINE
NOT USED
OUTPUTS {
PROCESSOR
PLOTTER SSANS F9,"
INSTRUCTIONS BREAK
Plotter in On-Line, Programmed-On State
RS-232-C/CCITT V.24INTERFACING 10-7