A wireless system is one in which the various devices, such as door contacts, motion detectors and glass break detectors, communicate with the control panel by radio signals instead of over a copper wire (hardwired). This is becoming a wireless world. The use of wireless alarm systems has grown tremendously over the last couple of years. Recent advances in battery technology have greatly reduced the need to replace batteries often. Plus, the battery life is monitored by the panel and the user gets a warning when the battery is getting low. If you have ever had a smoke detector start beeping in the middle of the night, you can be sure that it was not your monitored smoke detector because the panel will tell you when the battery is low, and it does not beep at the detector. Another reason for the popularity of wireless systems is aesthetic. With no wires to run, there are no exposed wires and fewer holes drilled into walls, floors and ceilings. The size of the devices has gotten smaller over time also. For homes with little or no attic space and for placing devices on the second floor of a two story house, wireless security systems are ideal.
There are times when you would choose a hardwired system. If the distance is too great, the power of the wireless devices might not be enough to cover the span between the panel and the device. Also, take into consideration what material the wireless signal must go through. Sheetrock and wood are not bad attenuators of the signal, but concrete and steel are dense enough to stop the signal from going through.
Security systems can be a hybrid of hardwired and wireless. For instance, the system can be hardwired when prewiring a newly constructed home and wireless for the stained glass front door that was decided upon at the last minute.