Both Montior and MixMonitor have a ‘B’ option that plays a periodic tone.
B([interval]): Play a periodic beep while this call is being recorded.
interval – Interval, in seconds. Default is 15.
Unfortunately, the majority of my customers are using 1.8. We do have some customers on Asterisk 11, but that doesn
In that case the only way I can think of doing it would be to place both parties into a conference call and have an extension join it which just plays a tone into the conference every so often.