One of the more cunning forms of electronic warfare has been the development of concealed surveillance cameras that use a wireless links to a base station. The U.S. Army has been using a system called NS 9200, from a company, NS Microwave, that makes similar equipment for police organizations. Much of the details of the NS Microwave equipment are confidential, as it includes cameras designed to be hidden in plain sight (built into outdoor and indoor items like metal fence posts or indoor furniture.) The wireless communications can also be encrypted, which is another item that has to be kept confidential. The systems bought by the army are mainly meant for outdoor surveillance, but there appears to be come indoor systems in use as well. The army has been eager to use more of these surveillance systems, because the technology is now cheap and reliable. In some cases, the troops have put their own systems together, using off-the-shelf components. What makes the NS 9200 system different is that it uses software that can identify some of the activity seen by the cameras, and alert troops to double check the video to see if something untoward is happening. Details of exactly how this works is also kept secret, lest actual, or potential, enemies can develop ways to defeat the software, or at least make it less effective.