You can administer a tone that notifies the parties on a call that the call is observed. You can administer the tone as a warning tone or a conference tone.
If you administer the tone as a:
Warning tone, the system generates a unique 2-second, 440-Hz tone before an observer connects to the call. While the call is observed, the system repeats a shorter version of this tone every 12 seconds.
Conference tone, the system generates the conference tone before an observer connects to the call. The system does not repeat the conference tone during the call.