Wireless experts from PA Consulting have used a Raspberry Pi to run a mobile phone basestation that operates a private network. The team hooked the Raspberry Pi up to a radio interface and, using Open Source software, implemented the functionality of a mobile basestation. Along with two mobile phones with sim cards, PA created all the functionality to make the phones talk to each other. PA set up its Raspberry Pi in a screened room to ensure no laws on frequency spectrum were broken.