MFJ-1278B MULTI-MODE BASIC OPERATION
Coding: If, prior to unbiasing, the value of the data byte is an ASCII p, q, or r, then the
received byte is a sync byte. Otherwise, the received byte contains actual display information
as described above. The color level of each pixel contain in the data byte is given below:
000 001 110 111
white lightest grey darkest grey black
NOTE: If the data byte is NOT a sync byte, you must remove the 30H bias BEFORE
extracting the pixel information.
For example, if an ASCII '9' is received, then the following steps should be taken:
1. Remove bias: 39H-30H = 9H
2. Extract pixel information: aaa = 001 bbb = 001
3. Display two pixels of lighest grey level.
If an ASCII 'p', 'q', or 'r' is received, then process the byte as a sync tone.
Saving SSTV Pictures to Disk
When the PRINTGRA command of the MFJ-1278B is ON, SSTV pictures received will be
sent to the graphics printer attached to the printer port. If PRINTGRA is OFF, the MFJ-
1278B will direct the picture graphics, in raw data format, to the user's terminal through the
RS-232C port of the MFJ-1278B. If your terminal program allows you to save a file to disk,
then you can save the picture on disk and re-transmit it later.
Terminating SSTV Printing
Printing of an SSTV picture can be terminated at any time during the printing. User will type
"ESC" then CTRL-C. Printing will stop and the MFJ-1278B will return to command mode.
Transmitting SSTV Pictures
The MFJ-1278B is capable of transmitting color and up to 16 gray level B&W SSTV. To
achieve this you must use a terminal program which support the multi-level SSTV data
format required by the MFJ-1278B.
Each level of gray is represented by a tone produced by the MFJ-1278B modem. The 19
tones which can be produced by the MFJ-1278B FAX/SSTV modem (in Hz) are:
1100, 1200, 1300, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000,
2050, 2100, 2150, 2200, and 2250.
The tone being transmitted determines the shade of gray in the picture. The sync tone of
1500 Hz is automatically generated by the MFJ
1278B. The other tones between 1550 Hz
