Ricoh M281 Series Service Manual page 813

Some possible problems
Garbled output:
If a string of characters (or binary data) is mistaken as a trigger and an incorrect PDL is
applied, the output will be garbled.
Incorrect printer settings:
Printer settings, for example the paper size, is incorrectly applied. This can happen when the
printer settings at the beginning of the job are initialized before a PDL switch occurred and no
settings were configured for the rest of the job.
Printer Bit Switch description
Bit Switch 2-3
This controls Auto PDL Detection by the PCL interpreter and PS interpreter.
BitSW 2-3=0 (default):
If PDL switching is applied to the job, all of the printer system, PCL interpreter and PS interpreter
will search for switching criteria (triggers).
BitSW 2-3=1:
Only the printer system will search for switching criteria (triggers). PCL/PS interpreters will not.
Bit Switch 5-3
This affects the PDL switching criteria (triggers) used by the printer system.
BitSW 5-3=0 (default):
"%%" is not used as a printer system PS trigger. "%%" will not call the PS interpreter.
BitSW 5-3=1:
"%%" is used as a printer system PS trigger.
The reason that "%%" is not included as a trigger by default, is that a string of text in the body of
the job such as the below, could result in a false positive. This would trigger a switch and result
garbled output.
%%%%%%%%%%%%%%%%%%%%%%%%%%%
However some customers prefer that "%%" be included as a switching criteria. BitSW5-3=1
should be used in such a case.

A side effect of BitSW5-3=1 is that "userdict" will no longer be used as a PS trigger.
Bit Switch 9-0
These determine whether Auto PDL Detection for print jobs transmitted via USB/parallel will wait
10 seconds to make sure the first 2KB of the job has been sent.
The Printer system portion of the Auto PDL Detection function is only performed on the first 2KB of
a job and can wait up to 10 seconds for that first 2KB to arrive. As the printer is unable to detect
the end of jobs submitted over a USB/Parallel connection, it might be preferable to not wait 10
seconds if jobs of less than 2KB are going to be printed. Enabling/disabling this waiting time is the
SM Appendix 4-5
Printing Features
D255/D256/M281/M282