Oki ML5590/91 User Manual page 41

Print Suppress Effective, Default = Yes
If your system uses the DC1 and DC3 codes for something other than
the print suppress mode, change the setting to No.
Proportional Spacing, Default = No
Change the setting to Yes to engage proportional spacing of
characters.
Protocol, Default = Ready/Busy
Appears only if the optional Serial Interface is installed. Change to
X-ON / X-OFF if that is the type of protocol your system uses.
Receive Buffer Size, Default = 64K
Selects the amount of memory devoted to holding received data.
Choosing 1 Line will tie up your computer while printing, but if you
abort the print job, the printer will stop much sooner.
Reset Inhibit, Default = No
Select Yes if you wish the printer to ignore the reset command sent by
software. This prevents your software from changing the settings you
make through the front panel controls or through printer commands.
This will also prevent your software from clearing out existing settings
when you finish printing one document and switch to another.
Serial Data 7/8 Bits, Default = 8 Bits
Appears only if the optional Serial Interface is installed. Change to 7
Bits if your system uses a 7-bit data format.
SI Select Pitch 10 cpi, Default = 17.1 cpi
IBM emulation only. Sets the pitch to be engaged when the printer
control panel is set for 10 cpi and the SI command is received.
NOTE
MENU MODE > 41