Patent ID: 7751386

Claim:
An IP (Internet Protocol) telephone apparatus connected to an ENUM (Telephone Number Mapping) server via a network, the ENUM server storing a NAPTR (Naming Authority Pointer) resource record of the IP telephone apparatus, the NAPTR resource record including a domain name corresponding to a URI (Uniform Resource Identifier), the domain name and the URI being associated with the IP telephone apparatus, the IP telephone apparatus comprising: a panel that includes a predetermined multi-function key, the predetermined multi-function key, when actuated by a user of the IP telephone apparatus, indicates that the user is unavailable, actuates a call answering function, and initiates an automatic deletion of the NAPTR resource record of the IP telephone apparatus stored in the ENUM server; and a controller configured to transmit, to the ENUM server, a request for deleting the NAPTR resource record of the IP telephone apparatus stored in the ENUM server, in response to the actuation of the predetermined multi-function key, whereby the ENUM server deletes the NAPTR resource record of the IP telephone apparatus from the ENUM server, and whereby, based on the deletion of the NAPTR resource record from the ENUM server, a user of another IP telephone apparatus connected to the network is notified that the user of the IP telephone apparatus is unavailable by a predetermined indicator lamp associated with the user of the IP telephone apparatus, the indicator lamp being located on a panel of the another IP telephone apparatus.