The present document specifies the Human Factors (HF) requirements related to all aspects of a European Telephony Numbering Space (ETNS). It describes the requirements to be met jointly by the ETNS service provider and the network operator enabling access to the ETNS service. The present document applies to any ETNS service provided within an ETNS scheme based upon a European Country Code (CC) and provided for access from public and private telecommunications networks. It covers those aspects of ETNS services that would be of importance to the users of those services and to other telephony users who may be affected by the introduction of an ETNS. Requiremen