SMS home routing is when a change made to the original GSM specification. The home routing enables mobile networks to offer a complete range of advanced services for both inbound and outbound SMS. This change provides functionality to mobile phone users and enables mobile operators an opportunity to generate additional revenue. It uses the Home Location Register (HLR) to change the flow of inbound off-net messages (messages that are not originating on the home network), directing them to an SMS router, rather than straight to target handsets. There, advanced services such as divert, copy, archiving and anti-spam can be applied before messages are delivered.