.TH VP 4 
.SH NAME
vp \- Versatec printer-plotter
.SH DESCRIPTION
.I Vp0
is the interface to a Versatec D1200A printer-plotter
with a Versatec C-PDP-11(DMA) controller.
Ordinarily bytes written on it are interpreted as ASCII characters
and printed.
As a printer, it writes 64 lines of 132 characters each on
11 by 8.5 inch paper.
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.
.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.
.TP
EOT
resets to the left margin, advances 8 inches, and then performs a FF.
.PP
The
.IR  ioctl (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 (default on open).
.br
.ns
.TP
040
Send remote terminate.
.br
.ns
.TP
020
Send remote form-feed.
.br
.ns
.TP
010
Send remote EOT.
.br
.ns
.TP
04
Send remote clear.
.br
.ns
.TP
02
Send remote reset.
.PP
On open a reset, clear, and form-feed are performed automatically.
Notice that the mode bits are not encoded, so that it is required
that exactly one be set.
.PP
In plot mode each byte is interpreted as 8 bits
of which the high-order is plotted to the left;
a `1' leaves a visible dot.
A full line of dots is produced by 264 bytes;
lines are terminated only by count or by a remote terminate function.
There are 200 dots per inch both vertically and horizontally.
.PP
When simultaneous print-plot mode is entered
exactly one line of characters, terminated by NL, CR, or
the remote terminate function,
should be written.
Then the device enters 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.
.PP
In print mode lines may be terminated either with
an appropriate ASCII character or by using the remote
terminate function.
.SH FILES
/dev/vp0
.SH "SEE ALSO"
opr(1)