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

13-20 The PCL Print Model EN
When using the 300 dpi User-Defined Pattern header (see Table
13-3). Set the eight bytes of header information to the following
values:
Byte 0 - Format = 0 (00 hex)
Byte 1 - Continuation = 0 (00 hex)
Byte 2 - Pixel Encoding = 1 (01 hex)
Byte 3 - Reserved = 0 (00 hex)
Byte 4/5 - Height in Pixels = 0 / 16 (00 / 10 hex)
Byte 6/7 - Width in Pixels = 0 / 32 (00 / 20 hex)
Byte eight begins the first bytes of binary data.
The PCL code below downloads the user-defined pattern and assigns
it an ID number of 3.
1 Specify the pattern ID number:
E
C
*c3G
Assigns an ID number of 3 to the pattern data which follows.
2 Send the User-defined Pattern command:
E
C
*c72W
Specifies that 72 bytes are to follow (8 bytes for header plus
64 bytes of pattern data).