Patent ID: 7885252

Claim:
An IP telephone apparatus comprising: a dialing unit that is used to input a telephone number of a call destination; a data obtainer that obtains, from an ENUM (Telephone Number Mapping) server, a NAPTR (Naming Authority Pointer) record of the call destination based on the input telephone number of the call destination, the NAPTR record comprising a list including at least one communication service available to the call destination, respectively associated with at least one specific number; a table that stores at least one communication service available to the IP telephone apparatus, arranged in ascending order of call rates, from a lowest call rate to a highest call rate; a retrieval unit that determines a lowest call rate communication service available to both the IP telephone apparatus and the call destination by sequentially searching the list of at least one communication service available to the call destination in the obtained NAPTR record, for each of the at least one communication service stored in the table, in ascending order of call rates, from the lowest call rate, and retrieves from the obtained NAPTR record, an available specific number that is associated with the determined lowest call rate communication service; and a transmitter that transmits a call to the call destination by using the retrieved available specific number, wherein the retrieval unit sequentially selects one of the at least one communication service available to the IP telephone apparatus stored in the table in ascending order of call rates from the lowest call rate, and determines whether the selected communication service is included in the list of at least one communication service available to the call destination in the obtained NAPTR record, and, upon determining that the selected communication service is included in the list of at least one communication service available to the call destination in the obtained NAPTR record, determines that the selected communication service is the lowest call rate communication service available to both the IP telephone apparatus and the call destination.