We would like to set up our Callamanager so that our alarm company can call all of our phones simultaneously in the event of an emergency. We would like to do so WITHOUT the use of a shared phone line. This is different than an intercom. We want whoever is in the building to be able to pick up whatever phone they are at and talk to the alarm company. We would prefer to not spend money but if there is an additional Cisco or third party app that will do this, we will consider it. Thanks in advance for your help.
Build a line group, hunt list, and hunt pilot. Put all your phones at the site in the line group and then point a DID at the hunt pilot.