If you have a wired system and can't wire for additional devices then the Honeywell 5800 series wireless transmitters are the way to go. These will also work with Honeywell's Lynx wireless systems as well whether it be the L3000, L5200 or the L7000. You can find a wireless device to match just about any hardwired device made. Some of the things that you can get in a wireless version are fire and smoke detectors, glass break detectors, temperature sensors, and also door/window and motion sensors.
No matter what your needs; Honeywell has a wireless solution for you.
Honeywell Wireless is trustworthy and secure and most Honeywell systems that can utilize wireless devices have a secure transmission between the panel and the devices themselves. Another feature of the wireless devices is that any panel that uses them will have RF Jamming detection in case you get a smarter than average thief who will think to use a jamming device to disable the wireless portion of the system. With the Honeywell wireless devices you'll get an average 200' radius of wireless transmission out from the receiver and if you need to go further than that they make a repeater.