Modem tones over television or radio

From: Hans Franke <>
Date: Thu Dec 10 10:35:47 1998

> Somewhat apropos the recent thread about sending mains power
> through modems, can anyone tell me if it's legal or illegal
> here in the States to send data in the audio of television or
> radio? Certainly there would be bandwidth and therefore speed
> limitations, but does the FCC allow this? Is it legal in other
> countries?

I guess it is perfect legal as long as you stay in band.
It is legal in Germany and we have (weiss Gott) a lot of
regulations. The WDR Computer Club (a TV and radio hobby
computer show of the WDR) this a lot of transmissions in
the mid 80s. AFAIR they also transmited programms using
the Teletext system - additional pages with binary
information have been inserted to distribute software.

But since programms started to grow beyond 1 to 10 KB,
the transmission times became unacceptabe - AFAIR the
bandwidth of teletext is less than two K-Byte per
second and they only could use some pages, since
'ordinary' TV viewers still wanted their information
pages transmited. On radio they cut of I think at 5
Minutes - so the maximum Programm was some 20 KB - all
transmission was done IN BAND, while via TV up to 200 KB
have been transmitted (in Austria at least).

At one time the stereo chanals (used as dual monao) have
also been used during the Show to transmit software - on
A (left) the regular sound was transmitted, while on B
(right) the software describen in the show was transmitted.

AFAIR the BBC did also transmit software thru teletext
pages (in GB).

Even in the DDR (east Germany) radio was used to transmit
home computer programms. I have several recordings from
DTF99 computer shows - at this times the whole east German
comuter hobbyist nation was recording the shows ... at
least that is what they told me :)


Ich denke, also bin ich, also gut
Received on Thu Dec 10 1998 - 10:35:47 GMT

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