HP PCL 5 Reference Manual page 244

Format (UB)
This is the first byte of every character data block header. It specifies
the format of the character descriptor and data. The format number
for Intellifont scalable fonts is 10.
Table 11-44
* These are described elsewhere in this chapter.
If the format number is different from that expected by the device, the
character is discarded.
Continuation (B)
This is the second (and last) byte of every character data block
header. It specifies whether the following data is the first (0) data
block of a new character definition, or a continuation (1) block for a
character definition which has already been received by the printer.
Because the value field in a Character Definition command is limited
to 32767 bytes, characters whose byte count exceed this must be
sent in two or more blocks. Table 11-42 shows the continuation block
for an Intellifont Scalable font.
Descriptor Size (UB)
This is the first byte of the character descriptor. It specifies the size of
the character descriptor in bytes. The typical descriptor size for
Intellifont scalable fonts is 2.
Class (UB)
Specifies the format of the character data. For Intellifont scalable fonts
values 3 and 4 are used, as described below.
11-62 Soft Font Creation
Value Format
4* LaserJet Family (Raster)
10 Intellifont Scalable
15* TrueType Scalable
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