Short for Radio over Internet Protocol (IP), RoIP is frequently used to describe an extension of VoIP using radio repeaters and base stations. Unlike VoIP, where two voice communication takes place between two telephones (or devices that act as telephones), RoIP is radio interoperability that is enabled through hardware devices, such as between new and legacy radio systems or land mobile radio and a computer or PDA. To work, devices are connected at base stations that are connected to IP gateways. At the IP gateway software will transcode the voice communication into IP packets which is then transmitted through to one or more other gateways to be converted into the language of the device being used. This is what enables the different types of devices to talk to each other.