The numbers, addresses and their ranges – collectively referred to as identifiers – that are necessary both for the operation of communication services and for the provision of services are scarce resources. Such identifiers include geographic (landline) numbers, mobile numbers, nomadic (non subscriber location-specific, IP-based) telephone numbers, numbers subject to special charges, the numbers of Internet access services, numbers of business networks, numbers used in machine-to-machine (M2M) communications, as well as short codes (such as the four or five-digit charity numbers).

Identifier-specific functions of the State, as well as their management, are being carried out in Hungary by the NMHH.

Available identifiers are contained in the national allocation plan of identifiers of electronic communications networks (ANFT), which sets out the division of identifiers between individual activities and services, as well as the type, structure and length of identifiers. Identifier use by electronic communication providers is subject to authorisation by the NMHH. The Authority maintains its own records on assigned identifiers.

When switching service providers, subscribers are allowed to maintain their old telephone numbers. This makes switching all the more flexible, as it is no longer necessary to inform all affected parties (e.g. banks, schools, family and friends etc.) about the change. Operated by the NMHH, the Central Reference Database (CRD) is a pivotal element in the technological implementation of number portability. Service providers are required to connect to the CRD and use its data whenever calls are being made to ported numbers.

Ever since number portability became a reality, area codes can no longer be used to determine the provider of a given telephone number. Instead, all it takes is a few clicks on http://szamhordozottsag.nmhh.hu/?lang=en an online ported number search page operated by the NMHH.