| 摘要 |
<p>A digital circuit transmission device which does not give speakers an incongruent feeling even when a voice codec is changed over in the same call for the purpose of making compatible efficient use with high quality of a circuit, and which comprises, both housed in an encoder, a first voice codec (7) having high quality and bit rate, and a second voice codec (8) having a low bit rate with not high quality, wherein these voice codecs are changed over based on control information that discriminates the traffic load of a bearer circuit (111) from an operation monitor/control unit (4). A silent portion of a voice signal input to a sound detector (31) in a signal detector (3) is searched to change over the voice codecs when it is detected.</p> |
