HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part I

10-6 User-Defined Symbol Sets EN
Encoded Symbol Set Designator (UI)
This field must match the ID code in the Symbol Set ID code
command.
This field contains the symbol set ID code. The symbol set ID code is
calculated from a symbol set ID selection value using the following
formula:
Symbol Set ID Code = (# * 32) + (ID - 64)
where # is the decimal number (0 to 1023) and ID is the ASCII
character code of the letter.
For example:
Assume the ID selection value selected for this symbol set is 17Q,
then:
(17 * 32) + (81 - 64) = 561
The symbol set ID code is 561.
Format (UB)
Set this field to 1 for MSL (Intellifont) or 3 for Unicode (TrueType).
Unrecognized values cause the symbol set definition to be ignored.
Symbol Set Type (UB)
This field defines the printable and unprintable codes for the symbol
set.
Bit Field Designated Use
0 7-bit, 32-127 are printable.
1 8-bit, 32-127 and 160-255 are printable.
2 8-bit, 0 - 255 character codes are printable,
however, to print codes 0, 7-15, and 27, the
printer must be in transparency mode.