Multi-spot call system, sound volume adjustment device, portable terminal device, and sound volume adjustment method used therefor and program thereof

摘要

The application relates to a multi-spot call system using push-to-talk over cellular (PoC) and methods for volume control in a portable terminal device participating in a multi-spot call. Each of the terminals stores a speaker's volume coefficient table, which is used for adjusting the volume of the different speakers at the terminal. Stored in each speaker's sound volume coefficient table (13) are a speaker identification ID and information of a voice coefficient so as to be correlated with each other. A speaker identification unit (11) extracts an each speaker's ID from a received packet based on floor control information or outputs the packet as an RTP packet to an RTP buffer. A sound volume control unit (12) executes a control program (14a) of a recording medium (14) to record a current speaker identification ID and reads a sound volume coefficient relevant to the speaker identification ID from the each speaker's sound volume coefficient table (13) to output the coefficient as sound volume control information. In this case, the sound volume control unit (12) increments/decrements the relevant sound volume coefficient based on sound volume adjustment information of a sound volume adjustment unit.