Microcom 438 - Manual (Page 104)

Chapter 6 Downloadable Graphics
438 Operator’s Manual - 880052-0100 6-3
3. Conversion is complete. Converted GRAPHIC file is ready to download to printer.
6.4 Graphic Download Methods
The printer supports both compressed and uncompressed graphic downloads. The
compressed format shortens the download time by reducing the number of bytes sent to the
printer. Please note that the compressed format is only usable on 8-bit data connections
and will NOT function on 7-bit data connections.
6.4.1 Uncompressed Graphic Downloads
The uncompressed converted GRAHIC file can be sent on either 7 or 8-bit connections, is
more flexible, and encodes using ASCII-HEX, but this method results in a much larger file
size than a compressed format.
The converted GRAPHIC file can be sent to the printer via any active printer port. A
terminal emulation program such as Hyper Terminal, ProComm, Tera Term, etc is
commonly used.
Note: It is highly recommended to use hardware flow control.
6.4.2 Compressed Binary GRAPHIC Downloads
The compressed format shortens the download time by reducing the number of bytes sent
to the printer. Data compression is accomplished by converting strings of 0 HEX or FF HEX
to shorter byte-plus-count sequences. These sequences are then expanded to the original
number of bytes inside the printer. A compressed binary converted GRAPHIC file must be
sent on a 8-bit data connection.
The printer must be setup to accept downloaded binary compressed files by setting
Software Switch #3, position 7 to “1”. Otherwise, the file may be sent to the printer through
any active printer port.
6.5 Advanced GRAPHIC Format Conversion for Programmers
The following sections are provided to developers who wish to create usable GRAPHIC
images within their own applications. Commands in the following section are not typically
seen for users using Microcom GRAPHIC utilities.
BMP format data:
Windows 3.X format.
dimensions: 74 wide, 31 high.
8 bits per pixel
Input file: Jet.bmp
Output file: Jet.mic
Output type: Model x24 Extended Binary (any size image) using font slot 100
Destination is ^D133 - for saving to flash (0)
Image width = 74 dots. Image height = 31 rows.
Image occupies 332 bytes of space in printer memory.
Decompressed file contains 1 FFs and 295 00s.