153.OFCOM may set general conditions to ensure that telephone users are able to communicate with every normal telephone number: this implements Article 6(1) of, and condition 4 of Part A of the Annex to the Authorisation Directive and Article 27 and 28 of the Universal Service Directive.
*a normal telephone number is defined in subsection (2) as a number allocated under the National Telephone Numbering Plan for the purpose of identifying the destination for, or the recipient of, communications which has been adopted by a communications provider as a number to be used for that purpose or which has been allocated in accordance with section 59 and is used for that purpose by a person other than a communications provider.