Epson Multi-mode Data Controller MFJ-1278B User Manual
Page 286
MFJ-1278B MULTI-MODE OPERATIONAL COMMANDS
TVX ON/OFF
Mode: SSTV Default: OFF
Parameters:
ON
Multi-level SSTV raw data is sent to the terminal without presetting the SSTV
format.
OFF
Multi-level SSTV raw data is sent to the terminal in format set by the TVMODE
command
TVX command sets the format that the MFJ-1278B sends the SSTV pictures to the terminal.
When TVX is turned ON, the SSTV picture format is not preset. The terminal program must
be responsible to detect the end of the SSTV picture. The MFJ-1278B does not detect the
end of the picture no matter what TVMODE is set. This means that MFJ-1278B can receive
any format of SSTV picture, like a "free running mode". It is not limited by the TVMODE
command. Picture lengths longer than 36 seconds are possible as long as the terminal
program can detect the end of the picture when the picture is being received.
When TVX is turned OFF, SSTV picture format is determined by the setting of the
TVMODE command. For example, if TVMODE is set to 5 (36 seconds format), the picture
sent to the terminal will end at 36 seconds. Which means that if you set the TVMODE too
short, you may not receive the whole picture.
TVX is automatically turned OFF when PRINTGRA is turned ON; this sends SSTV picture
being received to the built-in printer port. When SSTV pictures are sent to the printer port in
4 gray levels when PRINTGRA is set to ON.
TXDELAY n
Mode: Packet Default: 33
Parameters:
n 0 - 120, specifying 10 ms intervals.
This value tells the MFJ-1278B how long to wait after keying up the transmitter before
sending data. Some startup time is required by all transmitters to put a signal on the air; some
need more, some need less. In general, crystal controlled rigs with diode antenna switching
do not need much time, synthesized rigs need time for PLL lockup, and rigs with mechanical
T/R relays will need time for physical relay movement. The correct value for a particular rig
should be determined by experimentation. The proper setting of this value may also be
affected by the requirements of the station you are communicating with.