| 摘要 |
PURPOSE:To economize circuit constitution by connecting between devices digitizing voice messages and accumulating the digitized signals through a voice circuit, transmitting a voice message as analog signal and transmitting control information as digital information during the voiceless section. CONSTITUTION:Voice messages are accumulated in an accumulating device VMS. A control part CTL designates the detection of a voiceless section more than a fixed period included in a transmitting voice message to a transmission control part MCS, and when the section exceeds the fixed period, stops the transmission of the message, designates the transmission of a carrier to an MODEM M/D and then transmits control information to a line L1. At the transmission of the voice message, the CTL reads out the message from the VMS to a transmission memory MS and the read-out message is D/A converted and sent to the line L1. An A/D converter and the MODEM M/D are connected to a line L2 in parallel and the signal through the M/D controls a reception control part MRC through the CTL to receive the analog signal and the control information. Thus, double communication transmitting and receiving signals simultaneously can be attained by a simple circuit. |
