NYPD also maintains the Domain Awareness System, a network that provides information and analytics to police, drawn from a variety of sources, including a network of 9,000 publicly and privately owned surveillance cameras, license plate readers, ShotSpotter data, NYPD databases and radiation and chemical sensors. The Domain Awareness System of surveillance was developed as part of Lower Manhattan Security Initiative in a partnership between the NYPD and Microsoft. It allows the NYPD to track surveillance targets and gain detailed information about them. It also has access to data from at least 2 billion license plate readings, 100 million summonses, 54 million 911 calls, 15 million complaints, 12 million detective reports, 11 million arrests and 2 million warrants. The data from the 9,000 CCTV cameras is kept for 30 days. Text records are searchable. The system is connected to 9,000 video cameras around New York City.