Oki 390/391 Handbook page 48

To activate the Rolling ASCII Test:
1. Be sure paper is loaded.
Caution!
For wide carriage Model 391 Turbo, be sure you have wide paper loaded!
2. Turn off printer.
3. Hold QUIET button for several seconds while turning printer on. (If printer sim-
ply turns on without starting to print, you didn't hold down QUIET button long
enough.)
Hexadecimal Dump Test
If you want to test the data your computer is sending to the printer, you can place the
printer in the Hexadecimal Dump Mode. When the printer is in the Hex Dump Mode,
all data received, including text and printer commands, will be printed in both hexa-
decimal and ASCII format.
In the ASCII format, all non-printable characters will be represented by a pe-
riod.
For example, this line of BASIC code:
LPRINT CHR$ (27);"0";CHR$ (30);"This is an example of a hexadecimal
dump."
would print like this:
ML390/391 Turbo Printer Handbook 41