Wired alarm system has cables connecting all the detection devices back to your control panel. This involves cables run around your house from each point. Most new houses have alarm cables pre-installed during construction.
Wireless detectors contain batteries and transmitters inside the sensors and enable them to send signals by radio-wave back to your control panel. This eliminates the need for cables and makes for tidier installations if the house has not been pre-wired for. Batteries last about 4 years and are monitored by the control panel.