[BC] dtmf tone filter solutions

[SteveOrdinetz]

Rich Wood wrote:

>Yes. And it scared the daylights out of most of us. When I was at 
>WACE the CBS system was known as Netalert. #9 was the "bend over and 
>kiss your butt goodbye" signal. The box would often come to rest on #9.

When did Netalert go away?  I'd guess sometime in the 90s?  It was 
still around in the late 80s, but the next time I worked at a CBS 
affiliate was around '02 or so, and it was gone then.