The built-in device that notifies a homeowner of a security threat that has triggered the alarm system. The volume of most alarms is in the 90-100 decibel range, about as loud as a motorcycle or a police siren.

A colorless, odorless toxic gas harmful to humans and animals in high concentrations. Also known by its chemical symbol, CO. Many home security providers offer systems with carbon monoxide detectors.

An alarm system that sends signals to monitoring centers through cellphone towers instead of a landline telephone connection.

The keypad that controls the functions and features of a security system.

A trained specialist who works with a security company’s monitoring network to keep a lookout for alarm signals and provide assistance to customers in an emergency. A dispatch operator attempts to contact the homeowner in the event of an alarm signal and, if the emergency is verified, contacts the local authorities.

Security devices that can be bought at a retail store or online, installed and monitored by the homeowner.

A digital cellular network originally developed for mobile phones. Some security systems use GSM in two-way voice features that allow direct communication between customers and dispatch operators.

A home security system that involves wired connections between the components and the control panel.

Technology that lets homeowners control and create electronic schedules for lighting, thermostats, door locks and security systems

A home security strategy that involves a professional security company electronically monitoring a customer’s property for alarm signals.