ITU-T Recommendations

Recommendation ITU-T E.115 specifies the protocol, called the directory assistance protocol, to be used for directory assistance information exchange among service providers. This supports assistance/inquiry as part of the international telephone operator service allowing detailed information about subscribers business categories, localities, provinces and streets to be retrieved. This Recommendation also gives a description of the principles and procedures to be followed in interconnecting different national computerized directory assistance services. It specifies a protocol that allows exchange of information retrieved from databases with very advanced search capabilities. It specifies two versions of the protocol. Version 1 specifies basic functions, while version 2 of the protocol provides enhancements and uses HTTP as the underlying service and uses XML for protocol encoding. Version 2 of the protocol provides support for different language groups and provides possibility for location-based services. Version 2.10 of the protocol provides important additions to allow directory assistance service providers to exchange information about the databases supported, the functionalities that are available and requirements on input quality.