The following is a sample ALTCHARS.DEF line to change Special Character #12 to a not-equals symbol. The PC display character set does NOT contain the not-equals symbol so the "not" symbol (169) is used to show this character on the screen. The printer string consists of three bytes: 61 (equal sign), 8 (backspace), and 47 (slash).
#12=N, 169, 61, 8, 47 <ALT>+<N> for not-equals symbol
The default definition for Special Character #17 was an N-tilde effected via <ALT>+<N>. Since the new definition for character #12 used <ALT>+<N>, the character #17 definition will be cancelled.
Except for cancellations, as above, only specified Special Character(s) are modified. Following is a subtle redefinition of Special Characters #20 & #21 that may only be appreciated by a Laser-Jet programmer.
#20=K,174,27,38,97 <ALT>+<K>
#21=L,175,72 <ALT>+<L>
<ALT>+<K> produces character #20 which is displayed as << (single character) and is sent to the printer as: ESCAPE (27), ampersand (38), and a lower case "a" (97).
<ALT>+<L> produces character #21 which is displayed as >> (single character) and is sent to the printer as an upper case "H" (72).
Typing <ALT>+<K>2160<ALT>+<L> displays as <<2160>> but is sent to the printer as <ESC>&a2160H which positions the next character 3.00 inches from the right (2160/720). Similarly <<+720>> advances the printer "cursor" by 1.00 inches.
Text outside the Special Character definitions is considered annotation and is ignored by QWERTY when reading ALTCHARS.DEF. In this sample ALTCHARS.DEF, there is a great deal of annotation -- however, it actually does redefine Special Characters #12, #20 & #21.
