handle special functions of the DASI 450 terminal
450 [ -f ]
The 450 command supports special functions of, and
optimizes the use of, the DASI 450 terminal, or any
terminal that is functionally identical, such as the Diablo 1620 or
Xerox 1700. It converts half-line forward, half-line reverse, and
full-line reverse motions to the correct vertical motions. It also
attempts to draw Greek letters and other special symbols in the same
The -f option sets up fast (1200 baud) output using the
ETX/ACK protocol. The following errors are possible when
It should be noted that, unless your system contains text processing
software, certain commands (for example, eqn,
nroff, tbl, etc.) will not work. Use
450 to print equations neatly, in the sequence:
Standard output is not a terminal.
Error when opening output terminal for read.
Output terminal did not respond to ETX.
Output terminal did not respond with ACK.
neqn file ... | nroff | 450
Use 450 with the nroff -s flag or
.rd requests when it is necessary to insert paper
manually or change fonts in the middle of a document. Instead of
hitting the RETURN key in these cases, you must use the
LINE-FEED key to get any response.
In many (but not all) cases, the use of 450 can be
eliminated in favor of one of the following:
nroff -T450 files ...
nroff -T450-12 files ...
The use of 450 can thus often be avoided unless special
delays or options are required; in a few cases, however, the
additional movement optimization of 450 may produce better
Make sure that the PLOT switch on your terminal is
ON before 450 is used. The SPACING
switch should be put in the desired position (either 10- or
12-pitch). In either case, vertical spacing is 6 lines/inch, unless
dynamically changed to 8 lines per inch by an appropriate escape
Some special characters cannot be correctly printed in column 1
because the print head cannot be moved to the left from there.
If your output contains Greek and/or reverse line-feeds, use a
friction-feed platen instead of a forms tractor; although good
enough for drafts, the latter has a tendency to slip when reversing
direction, distorting Greek characters and misaligning the first
line of text after one or more reverse line-feeds.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003