ITU-T Recommendation 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. This Recommendation also gives a description of the principles and procedures to be followed in interconnecting different national computerized directory assistance services. 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.