.TH VP 4
.UC
.SH NAME
vp \- Versatec printer-plotter
.SH DESCRIPTION
.I Vp0
is the interface to a Versatec 1200A printer-plotter
with a Versatec C-PDP-11(DMA) controller.
In print mode bytes written are interpreted as ASCII characters
and printed.
The format is 64 lines of 132 characters each on
11 by 8.5 inch paper.
(The printer will perform an automatic form feed at the bottom
of a page.)
Only some of the ASCII control characters are interpreted.
.TP
NL
performs the usual new-line function, i.e.
spaces up the paper and resets to the left margin.
It is ignored, however, following a CR which ends a non-empty line
or if the print buffer is already full.
.TP
CR
is ignored if the current line is empty but is otherwise
like NL.
.TP
FF
resets to the left margin and then to the top of the next page.
Do not use in SPP mode (see below).
.TP
EOT
resets to the left margin, advances 8 inches, and then performs a FF.
Do not use in SPP mode.
.PP
The \fIioctl\fP\|(2) system call may be used to change the mode of the device.
Only the first word of the 3-word argument structure is used.
The bits mean:
.TP
0400
Enter simultaneous print/plot mode.
.br
.ns
.TP
0200
Enter plot mode.
.br
.ns
.TP
0100
Enter print mode (resets SPP mode, default on open).
.br
.ns
.TP
040
Send remote line terminate.
.br
.ns
.TP
020
Send remote form-feed. (Illegal in SPP mode.)
.br
.ns
.TP
010
Send remote EOT. (Illegal in SPP mode.)
.br
.ns
.TP
04
Send remote clear.
.br
.ns
.TP
02
Send remote reset.
.PP
When the device is opened
a reset and clear are performed automatically.
When the device is closed an end-of-transmission signal
is automatically
sent to advance the last written page past the
toner developing bath.
Notice that the actual device mode control bits
(PRINT, PLOT, SPP) are not encoded with the remote functions
and it is therefore required that exactly one of these
be set for each
.I ioctl
call.
.PP
In plot mode each byte is interpreted as 8 bits
with the high-order bit plotted as the leftmost dot;
a `1' leaves a visible dot.
A full line of dots is produced by 264 bytes;
lines are terminated only by count or by sending a
remote line terminate function.
There are 200 dots per inch both vertically and horizontally.
.PP
Simultaneous print/plot (SPP) operation is provided to
permit direct overlaying of character data generated
by the internal character generator, with plotting data
generated on a dot-by-dot basis.
.PP
When simultaneous print-plot mode is entered
exactly one line of characters, terminated by
an NL or CR character, or the
remote line terminate function, should be written.
The device should then be set to plot mode and
at least 20 lines of plotting bytes should be sent.
As the line of characters (which is 20 dots high)
is printed, the plotting bytes overlay the characters.
Notice that it is impossible to print characters on baselines
that differ by fewer than 20 dot-lines.
New data can only be entered into the print buffer
after the last scan of the previous line of characters
is complete.
.PP
In print mode lines may be terminated either with
an appropriate ASCII character or by using the
remote line terminate function.
.SH FILES
/dev/vp0
.SH "SEE ALSO"
vpr(1)
.SH DIAGNOSTICS
.I Errno
is set to ENXIO if an
.IR open (2)
fails because the device is already in use by another process.
.PP
.I Errno
is set to EIO if
.IR open " or " write (2)
fail because the power is off or the paper supply is depleted.
A diagnostic message is printed on the console terminal
on the first occurrence of one of these errors.