Citizen CBM-910 Series User Manual page 40

NOTE)
With 0 being set in "C1" parameter even if data have been registered in the uppermost position,
letter image registered is made incomplete.
(11) Registered Letter Valid / Invalid (ESC + "%" + n) Command
Whether a registered pattern is valid or invalid is set with ESC (1BH) + "%" (26H) + n code being input.
n = 1 (01H) : Registered pattern to be made valid. (Addresses for which no registration change has been conducted
are taken as inside fixed characters.)
n = 0 (00H) : Registered pattern to be made invalid. (Taken as in side fixed character sets.)
The initial setting is 0 (inside fixed character).
Even with letters already registered by pattern registration, printing of registered letters cannot be effectuated
unless the patterns registered are mode valid with this command.
NOTE)
This command is applicable only to the 40-column printer.
CITIZEN 35
CBM-910 User's Manual