The audio bandwidth over telephone connections is too low to support
full-motion video. However, amateur radio operators have been sending
color pictures over the airwaves using the small audio bandwidth for many
years. This would work just as well over the telephone.
Read about SSTV (slow scan television) which sends pictures with audio
modulation. It fits neatly within a 2.6 kHz bandwidth, and is suitable
for telephones and all sorts of audio recordings. Search the Internet for
SSTV and you'll get lots of hits, such as this one:
To make the pictures fit into audio, each frame takes a few seconds to a
couple minutes, depending on the picture's resolution and number of
colors. You give up motion, but the pictures are quite nice.
Equipment? SSTV can be built quite cheaply using a computer with a sound
card. Free software is available from ham radio web sites.
There is another alternative, too. If you're going to use a computer
anyway, then an ordinary modem connection is better optimized to send
data and digital pictures across the phone lines.
Good luck, Barry
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I want to send a video by telephone line, but i dont know how to
start. I'm looking for a circuit that modulate the telephone line with a
video sinal and at the other end it demodulate to see this image in
a tv. Please if any one can give me an idea or help, send me that.
