Assisted Monitoring Questions

A Question about the assisted Monitoring. A couple of times I have accidentally set the alarm off by mistake. Does the alarm after it is set off wait a certain amount of time before it starts to contact (call) the emergency contacts. As anytime I have set it off I have just had the usual notifications to say it has been set off but have never had a call. But have always turned the alarm off within about 20 seconds of it being activated.