Transmitting:

Tranmission is similar to reception; If you have not yet read the section
on receiving SSTV, please do so now.

In general, to transmit, you need to set the AVT to the correct
transmission mode, and press the TX button. The only exception to
this are the Robot composite color modes; if you wish to transmit in one
of these modes, you must first open the RoboSynth window and select
the correct speed - the system will create a transmit record
(we refer to this process as 'compiling', here at Black Belt Systems)
and then return you to the main control panel.

The AVT uses the Amiga's sound hardware to transmit SSTV and FAX images.
The Amiga has a four channel, highly sophisticated digital sound
synthesis system that runs using DMA and Interupt control within the
computer, and requiring no external hardware at all.

In the SET window, you will find five (or six, if you own and a500
or a2000) controls that affect the transmitted signal.

Channel selection
There are four channel buttons; these choose which of the four Amiga
sound channels you wish to utilize in the production of SSTV and FAX
AFSK signals. The default is Channel 1.

Low Pass Filter
The low pass filter button controls, in a500's and a2000's, whether
the AMiga's internal filter is on or off. it also controls the Amiga's
power indicator - so if you see that the Amiga's power indicator is off
or dim, check this button before panicking. On an unmodified a1000, this
button ONLY controls the power indicaator - sorry about that. An issue
of Amazing Computing detailed how to modify the a1000 so that the low
pass filter could be turned on and of just like the a500 and the a1000.

Multiple Frame Tranmission
If you press the MEM button, the memory control window will open, and
you can select some additional transmit operations. First, you can
press the arrow buttons to change the transmit repeat count. For instance,
you might want to set it to four. Once that is done, you can press the
TxRp button, and the AVT will send, in the currently selected mode,
four frames of the image in the current memory. If you press the Sq
button, another window will open. here, you can set up a sequence of
frames to be transmitted that are in different memories. For instance,
you could put a picture of your dog in memory 1, your cat in memory 2,
and yourself in memory 3. Set the Begin value to 1, anf the end value
to 3. now close the wondow, and press the TxSeq button. Out they go,
one after another. You can also receive sequential images the same
way - just set up the begin and end values, and press RxSeq.

Transmission of individual modes

RGB frame sequential transmission
This is very simple. Press the speed you wish to use (8,17a,17b,34),
then poress the 111 buitton, and the TX button.

FAX Transmission
Just press TX. Note that if you are running with a 1 megabyte machine,
you will only be able to transmit data from the screen itself, not
the FAX memory (since you won't be able to HAVE a fax memeory). This
measn that the effective resolution of your FAX images is 640x400.
If you do have extended memory, and you did not get a requester
indicating that you were unable to allocate the memory, then the
FAX transmission is senbt in 1024x1200, in 16 grey levels. You need to
ensure that you have selected the correct fax mode as well from the
two available - Weather fax (120 lpm) and news fax (60 lpm).

Black and white transmission
Press the R, G, or B buttons, select the speed from either the Robot
mode group (8,12,24, and 36) or the standard/AVT mode group
(8,17a,17b, or 34), and press the TX button.

AVT transmission
Select the speed from the std/AVT mode group (24, 90, or 94), press
the AVT button, then press TX

Robot Color transmission
Press the RoboSynth button, select the appropriate speed from the four
in the Robosyth window (NOT the std control panel) and wait for the
conversion to complete. Once complete, the RoboSynth window will close,
then you press teh TX button.

Standard line sequential color transmission
Press the 25.5, 51, or 102 buttons, then press TX.

Volker-Wrasse line sequential color transmission
Press the 25.5, 51, or 102 buttons. Then press Tx. You must ensure that
the V-W button in the SET window is selected (red light showing) or these
buttons select only standard line sequential modes.