A media gateway is a translational device that is used to convert various types of digital media protocols for effective multimedia communication. Media gateways are widely used in connecting different networks (such as 2G, 3G, 4G and LTE), hence their main function is to convert different coding and transmission techniques to enable communication between the networks.
Media gateways make multimedia communications possible over next-generation networks on multiple transport protocols such as Asynchronous Transfer Mode (ATM) and Internet Protocol (IP). A media gateway is simply a piece of hardware containing different functions and algorithms to perform conversions of multimedia transfer protocols to send and receive them over different types of networks. Media streaming functions such as data noise cancellation, channel noise and error removal are also performed on a media gateway.
Media gateways are often confused with VoIP gateways, but both are in fact different technologies.