Patent ID: 8774388

Claim:
A telephone terminal, comprising: a memory for storing a plurality of codec programs with respective priorities, each of the codec programs being executed to code and decode voice signals; a codec selection processor operative to negotiate with a partner telephone terminal to use a common codec program from the codec programs, the common codec program being stored at both the telephone terminal and the partner telephone terminal; a voice processor operative to execute the common codec program to code and decode voice signals during voice communication with the partner telephone terminal; and a transmitting processor operative to transfer a particular codec program stored in the memory to the partner telephone terminal over a communication network, wherein the codec selection processor selects a codec program, which is not stored at the partner telephone terminal and has a higher priority than a priority of the common codec program, from the plurality of codec programs stored in the memory, during the voice communication in which the voice signals are coded and decoded by executing the common codec program, the transmitting processor transfers the selected codec program to the partner telephone terminal during the voice communication in which the voice signals are coded and decoded by executing the common codec program, the transmitting processor transferring the selected codec program together with a deletion condition instructing the partner telephone terminal to delete the selected codec program after the voice communication is completed, and the deletion condition instructs the partner telephone terminal to delete the selected codec program after a designated number of voice communication sessions have been completed without using the selected codec program, and the voice processor switches from executing the common codec program to executing the selected codec program during the voice communication in which the voice signals are coded and decoded by executing the common codec program.