450 -- 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 manner as 300(C).

The -f option sets up fast (1200 baud) output using the ETX/ACK protocol. The following errors are possible when using -f:

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:

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 aligned output.


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 sequence.


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.

See also

300(C), graph(ADM), mesg(C), stty(C), tabs(C), tplot(ADM)
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003