Apple II Technical Notes Developer Technical Support
Revised by: Matt Deatherage November 1988
Written by: Rilla Reynolds October 1986
This Technical Note documents an ImageWriter II firmware bug which affects custom font selection.
Due to an ImageWriter II firmware bug, the ESC ' command neither selects nor reselects custom font 1 after custom font 2 is selected, unless you fix an errant pointer with the following command sequence first:
7-bit mode: ESC Z 00 20 ESC D 00 20 ESC '
8-bit mode: ESC Z 00 20 ESC '
The ESC ' command works correctly on an ImageWriter I, but the sequence above is also acceptable; therefore, it is in your best interest to always utilize the given sequence to select custom font 1. It is possible that the printer was initialized and custom font 2 was selected long before your program was launched.