City ID is a caller information software product created by Cequint Incorporated. City ID displays the North American city and state (primarily USA and Canada) of a calling phone number based upon the phone numbers area code and exchange. As of March 2011, Cequint has integrated City ID with over 30 handsets spanning five cellular phone Operating System platforms. These platforms include Blackberry, JME, BREW, BREWMP, Android, and Windows Mobile. Cequint has worked and continues to work with all major United States cellular carrier companies including Verizon Wireless, AT&T, Alltel, U.S. Cellular and T-Mobile. The City and State information is determined by referencing an area code and exchange (NPA-NXX) of a phone number from a database stored locally on the handset. This database may be updated periodically over a communications channel using standard client-server application layer methods. The database lists the locations where blocks of phone numbers with a given area code and exchange prefix were initially registered. The City ID application returns the City and State results to the cellular phones Operating System which displays this information on call screens. The particular position and font of the City and State text is determined by the cellular phone software team. Cequint assists these teams in integrating the City and State lookup and subscription management.