OpenBTS is an open-source software project that allows users to create their own mobile phone networks. It enables the use of standard mobile phones to connect to a network without relying on traditional cellular infrastructure. This technology is particularly useful in areas with limited access to commercial mobile services. The project works by emulating the functions of a GSM base station, allowing users to make calls and send text messages. OpenBTS can be deployed on inexpensive hardware, making it accessible for communities and developers interested in building localized communication systems.