Talk show "beep"

[Russ Butler]

The early talk shows had an audible "beep" (every ten seconds, was it?) 
to let the caller and listeners know that the conversation was being 
recorded or that it was on the air live.   Did it the seven-second delay 
replace the "beep" or was that much later on?

Also, did that "beep" come from the recording equipment or some other 
technical mechanism in the phone line set up?  I remember some comedians 
would refer to the telephone "beep"  in their routine. 

When was the "beep"finally eliminated from onair conversations?  It must 
have been a legal issue of protecting privacy rights to remove/replace 
that "beep" notifier to callers with the delay button and a seven-second 
delay protection in addition to controlling obscenity speak.  (Look how 
onair language is today, Howard Stern et al notwithstanding!)

=Russ  songbook2@comcast.net