| 摘要 |
PURPOSE:To achieve switching from the transmission of only a voice to the simultaneous transmission of a voice and data by generating control information by varying the least significant digit bit of voice data successively and by sending this control information to a reception side. CONSTITUTION:When a request for switching from the transmission of only a voice to the simultaneous transmission of a voice and data is generated at a transmission part, a control information generating circuit 7 outputs control information 20 and a control-information insertion control signal 21, and a pattern suppressing and control-information inserting circuit 6 inserts a prescribed bit pattern into the least significant digit bit of the voice data. After the control information is sent, a selector 4 is controlled by a selector control signal 19 to transmit the data and voice simultaneously. At a reception side, the least significant bit 36 of the received data is inputted to a shift register 28, whose output is inputted to a control pattern detecting circuit 29 composed of a read-only memory, etc., stored with various patterns previously, thereby detecting a control pattern. |
