The silent tone is an inaudible 20 milliseconds file that will trigger ad-breaks on your radio station.
We recommend to mix it directly at the end of your jingles, however you can also insert it directly on your programming.
You can download the tone here:
http://marketing.shoutcast.com/Bip%2027Hz%20stereo%20180%20deg.wav
Your station must be set in the monetize tab of the radio manager, to change your parameters click on "change settings"