USER’S GUIDE
Appendix–46
CCITT G3/G4 (original command)
One of the unique features of the PCL mode of this printer is it
supports CCITT G3/G4 type data compression format.
■ CCITT G3/G4 (Raster Graphic Mode 1152)
The printer’s PCL mode supports CCITT G3/G4 type graphic
data compression.
This format is popular in optical document storage area as this
compression is effective to store black and white type pictures.
Compression mode for CCITT G3/G4 is 1152 and the command
becomes
ESC * b 1152 M.
As G3/G4 format does not have picture size/resolution
information, the printer requires a header at the beginning of
the picture data. The header size is 94 byte. Both the header
and the picture data are transferred by one transfer graphics
data command (ESC * b ### W). Normal PCL transfer graphics
data command has a limitation of the data size and ### should
not exceed 32767. Unlike other mode, mode 1152 is special and
this mode does not have 32767 byte size limitation.
Print model is not applied to this type of raster graphics.
The mode 1152 graphic data consists of the following data
structure. The picture data follows the header.
Header 94 bytes
File length
Picture = ####
CCITT G3/G4 data of ESC*b####W
Picture Data length
Header format is described on the next page.
You have to specify mode 1152 by sending ESC *b1152M
command for each graphic data transfer.
About CCITT G3/G4 data format, please refer to CCITT (THE
INTERNATIONAL TELEGRAPH AND TELEPHONE
CONSULTATIVE COMMITTEE) BLUE BOOK Volume VII.