b'existing services like Short Message Servicedigital, GSM is considered a second generation (SMS) and Multimedia Messaging Service(2G) mobile phone system. Many GSM (MMS). GPRS packet-based services are fasteroperators have roaming agreements with and cost less than circuit-switched servicesforeign operators thus making it possible to since communication channels are used on atravel to different countries and have your GSM shared-use, as-packets-are-needed basisenabled phone continue to work. All devices instead of dedicated to one user at a time. Inthat work on the GSM network utilize theory, the connection only has to be there toSubscriber Identity Module (SIM) Cards that complete the packet handoff instead ofcontain the home network access continuously connected while all the data isconfigurations for that device. transferred. GPRS data transfer is typicallyHardwired Security System: A security system charged per kilobyte of transferred data, whilethat has alarm devices connected to a control data communication via traditional circuitpanel by low-voltage wires. switching is billed per minute of connection time, independent of whether the user hasWhile equipment for hardwired security actually transferred data or has been in an idlesystems is less expensive than wireless state.equipment, installation and service of Glassbreak Detector (GBD): A security systemhardwired systems far outweighs the difference device that detects the frequency of brokenin upfront equipment costs. Because multiple glass. A glassbreak detector has a highlydevices are programmed into a hardwired zone, sensitive microphone that can distinguishwhen one goes bad it is very hard to between different sound frequencies andtroubleshoot the problem. You would have to recognize the exact frequency of broken glass,check the wire connection and the alarm which if detected causes an alarm. GDBs alongtransmitter for every device on that zone. With with motion detectors are devices used forwireless security systems, each device is its own interior protection to provide another layer ofzone, so if a zone has a trouble you know protection beyond perimeter protection. If youexactly which device needs service. only had door/window contacts, then a criminalHeat Detector: A burglar alarm or fire alarm that breaks the glass without actually openingdevice that detects a preset high temperature the door or window would go undetected. Oneor a rapid rate-of-rise (ROR) in temperature. GBD can usually protect every window in aHeat detectors can be either electrical or room and should be mounted on the wallmechanical in operation. The most common across from the windows it is meant to protect.types are thermocouple and electro-pneumatic, GBDs are preferable over motion detectorswhich both respond to changes in ambient when large animals live in the alarms premise,temperature. If the ambient temperature rises since they work while the security system is inabove a predetermined threshold, then an stay mode without causing false alarms.alarm signal is triggered. Global System for Mobile CommunicationsHeat detectors are better than smoke detectors (GSM): GSM is a digital mobile telephonyfor areas where smoke would normally be system and is the most popular standard forfound such as a kitchen or smoking lounge, as mobile phones in the world. Its promoter, thethey would not cause false alarms. GSM Association, estimates that 82% of the global mobile market uses the standard. GSMHidden Camera: A discrete security camera differs from its predecessors in that it digitizesused to film people without letting them know and compresses data. Because the data isthey are under surveillance. The camera is 84'