3. A call-processing arrangement for use in a telecommunications system having a plurality of endpoints and having a network numbering plan for addressing the endpoints, wherein callers supply sequences of symbols to specify treatment that is to be given to calls, each sequence comprising at least one symbol string that is defined for the network numbering plan, comprising: defining means for defining the network numbering plan, the plan comprising a plurality of types of symbol strings, and addresses of at least some of the endpoints of the system within the network numbering plan each comprising a plurality of symbol strings of a plurality of the types; identifying means cooperative with the defining means and responsive to receipt of a symbol sequence including a plurality of symbol strings of a plurality of the types, the included symbol strings appearing in the symbol sequence in any order, for using the defining means' definition of the network numbering plan to identify the included strings irrespective of their order in the received symbol sequence; and means responsive to the identification, for effecting establishment of a connection to an endpoint of the system having an address within the network numbering plan formed by the identified included symbol strings, irrespective of the order of the identified included symbol strings in the received symbol sequence.
3. A call-processing arrangement for use in a telecommunications system having a plurality of endpoints and having a network numbering plan for addressing the endpoints, wherein callers supply sequences of symbols to specify treatment that is to be given to calls, each sequence comprising at least one symbol string that is defined for the network numbering plan, comprising: defining means for defining the network numbering plan, the plan comprising a plurality of types of symbol strings, and addresses of at least some of the endpoints of the system within the network numbering plan each comprising a plurality of symbol strings of a plurality of the types; identifying means cooperative with the defining means and responsive to receipt of a symbol sequence including a plurality of symbol strings of a plurality of the types, the included symbol strings appearing in the symbol sequence in any order, for using the defining means' definition of the network numbering plan to identify the included strings irrespective of their order in the received symbol sequence; and means responsive to the identification, for effecting establishment of a connection to an endpoint of the system having an address within the network numbering plan formed by the identified included symbol strings, irrespective of the order of the identified included symbol strings in the received symbol sequence. 5. The arrangement of claim 3 wherein: the defining means further define the network numbering plan such that the symbol strings of individual types have variable lengths in terms of numbers of symbols that make up individual symbol strings of the individual type.