I-Data 5250 ALLY - Manual (Page 167)

Page A-5 APPENDIX A — INTERFACING XEROX PRINTERS
Auto Form Feed Suppression
Auto FF suppression is initiated in the same way as Auto PFS suppression,
although there is a separate configuration option to select whether or not
this occurs.
Because Auto FF suppression is particularly useful for form download
jobs, it is possible to configure FF suppression to be initiated by
s
+M d or s +N d (both of which initiate a form-based job) but not
s +P d or s +Q d. This is in addition to the standard Auto FF
suppression mode that is initiated by any of the four commands.
Passing FFs in Auto FF suppression mode
Because Auto FF suppression mode is active for the duration of the XES
job, a method is necessary to pass Form Feeds to the printer. The method
the 5250 ALLY uses is designed to take advantage of the behavior of XES
printers.
If an XES mode printer receives a job begin command while a job is
currently active, it prints the current page and begins a new page as an
effect of starting the new job. Many existing applications take advantage
of this behavior and use job start commands as Form Feed commands.
This use of the job start command works well on most Xerox printers, but
it fails when used on 4235 printers. Each page is considered by the 4235
printer to be a separate job. 4235 printers treat a job as a logical unit in the
way they spool and print data. Some possible effects of printing each page
as a separate job are: the job queue quickly becomes cluttered; each page
may be offset in the output tray; and the printer throughput may be
noticeably reduced.
When the 5250 ALLY is in Auto FF suppression mode, it enforces the rule
that the current job must be ended before starting a new job. For the
duration of the current print job, the XES command used to begin the job
may be used as a Form Feed command. The 5250 ALLY will
automatically translate this command into a Form Feed to avoid the
problems caused by having only a single page per job.
In this example, the column on the left shows the data stream for a print
job, and the column on the right shows the 5250 ALLY’s output: