While this is not a true key switch, it appears that way to the control. The 2 way devices are more expensive but they do confirm that your command was received and carried out. Most systems limit the functions of wireless command stations so it is important that you have at least 1 wired station as part of your system. These relays can allow you to perform many functions such as sprinkler control or as a means of interfacing with a home automation system. The number of available relays depends upon the control used, but some manufacturers have the ability to connect over 100 outputs to the system.
Most controls provide multiple user codes.
This allows the user to assign each operator of the system their own code, making it easy to remember. Having the ability to add or delete codes can be very useful when you have weekend guests or employ a baby-sitter. You can assign them a simple code and then delete it after they no longer need it, keeping your code secure and your security intact. If your control has a viewable memory log you can review it and determine exactly who performed a function and at what time, an easy way to tell if the curfew was violated or if the system was armed when your spouse went shopping. This allows you to keep the system active for your safe while the rest of the security system is off.