Systems, apparatus, methods, and computer program products for a security system to automatically notify by wireless communications means selected classes of recipients of the occurrence an alarm event, receiving acknowledgment of the receipt of the alert by the recipient, receiving either a digital or a vocal message, and responding appropriately to the reception. The recipients may be provided with handheld transceivers that have been assigned to one of a plurality of communications channels. The system includes a communications interface that allows a central computer, in response to an alarm, to locate a communications channel and message text for transmission to a selected group of recipients. The computer system may then programmatically select the communications channel, convert the message text into an audio, synthesized voice message, and send the message to the recipients on the selected communications channel. The recipients may respond to the message with a code entered on a keypad of their handheld transceivers.