Agilent Technologies 5250 user manual Line Feed vs. Relative Movements

APPENDIX A — INTERFACING XEROX PRINTERS Page A-11

Input to OPTIMA:

sx20,200,5sx40,400,5d

Output from OPTIMA:

sx20,200,5d

sx40,400,5d

In the example above, when the OPTIMA encountered the second UDK character, it automatically terminated the previous UDK command. This termination was provided only because the previous command (sx — line draw) requires a line ending termination. If the previous command does not require a line ending termination, none will be inserted.

This feature does not require any special mode to be entered; it is part of the natural behavior of the OPTIMA. There is no limit to the number of commands that can be placed on a single line, except that the line length limit (MPP — Maximum Print Position) must not be exceeded. This feature can be useful in reducing the number of lines of text required to encode a data stream, and it can be used to eliminate the requirement for FF suppression for some less complex documents.

Line Feed vs. Relative Movements

When the OPTIMA is emulating an IBM printer, it normally uses relative vertical movements to simulate the line spacing requested by the system. This behavior has several advantages over set-line-density-then-line-feed type vertical movement methods:

1)Line density is under direct system control regardless of the font selection. This is the same behavior as the IBM printers that the OPTIMA emulates.

2)Use of this method allows the reduction of line spacing to 70% of the system requested value during COR (Computer Output Reduction) jobs. This is the same as IBM printers.

3)The system controls line density using either 1/72-inch units or 1/1440-inch units. The Xerox printer allows line density to be set only in 1/300-inch units. For some system-supported line densities, the closest line density in 1/300-inch would be in error. This error would accumulate as text moves down the page. The OPTIMA normally maintains vertical positioning information in the system’s 1/1440-inch resolution. Each line of text is placed within one-half pixel of its correct position. There is no error accumulation.