| 摘要 |
PURPOSE:To prevent deterioration of a communication quality by matching the kind of a CODEC used for both radio terminals, and relaying a radio encoded audio signal without executing its code conversion in a network. CONSTITUTION:In the case that a radio terminal 2-1 and a radio terminal 3-1 execute an audio communication, when the transmitting radio terminal 3-1 designates a radio encoded audio signal B, a request for changing the radio encoded audio signal to be used is sent out to the terminal 3-1 to the effect that both the terminals use the same radio encoded audio signal A in accordance with the radio encoded audio signals A, B which both the radio terminals can use by an audio encoding matching circuit 10 in an exchange 5. In the radio terminal 3-1, a CODEC selection control circuit 17-1 is operated, and a CODEC in the radio terminal 3-1 is subjected to connection change from a CODEC 11-1 to a CODEC 12-1. Also, in the exchange 5, selectors 8-1, 8-3 are controlled by a control circuit 9, CODECs 6-1, 7-1 are detached, and only a channel 14 is connected. |
