[BC] Tones to switch program...

[Burt I. Weiner]

At one time there was an FCC rule that in effect said that you could 
not use tones or other "means" that could allow the listener to mute 
main channel program material.  I believe this rule actually came 
about with the advent of SCA's on FM.  Back in the dark ages when FM 
was considered a cheap delivery method for background music services, 
many FM stations were transmitting a 20.4 kHz tone to mute receivers 
in businesses that subscribed to the service.  This was eventually 
disallowed, which ushered in the SCA.

Burt

At 03:00 AM 9/19/2008, broadcast-request at radiolists.net wrote
>Dave Hultsman
> >From NAB Austin
>
> > In fact, when I was in Radio, CBS was sued because they used some
> > audible high-frequency squitter to signal over the network. Since it
> > was within the normal program audio band, the FCC disallowed its use
> > and CBS had to replace their queuing boxes with ones that used
> > sub-audible tones.

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net
K6OQK