mask.of.sanity writes "Cheap home alarms, door opening systems and wireless mains switches can be bypassed with low-cost and home-made devices that can replicate their infrared signals. Fixed-code radio frequency systems could be attacked using a $20 'toy', or using basic DIY componentry. Quoting: 'Criminals might be able to capture IR signals if they can get a line of sight to when the system is being armed or disarmed. If a criminal knows what type of alarm system you're using then they could do what we did here and reverse it for cloning a remote. A more likely scenario is just to buy a duplicate system and use that remote. Not all IR remotes can be switched from the same system. It depends on whether a code is being transmitted and how many variations of the code and remote exist. In the system described in this post, there is no code, just a carrier signal. If a code is being transmitted, then the Infrared toy can capture it and replay it. So that's your best bet for a criminal looking at a completely unknown remote.'"