| 摘要 |
PROBLEM TO BE SOLVED: To provide the picture transmission of high dignity by transmitting picture/sound data through the use of a digital line while an existed telephone set connected to an analog communication line is connected. SOLUTION: Call information in an audio telephone system 41' is sent to an audio telephone system 41 through an ISDN line 87. When CPU receives the information, a CALL sound is generated and a calling picture is displayed. CPU detects the off-hooking of the audio telephone system 41' and causes DSP to execute control for executing a connection processing with an ISDN line 87. When CPU detects response information from the audio telephone system 41' on an audio telephone system 41 side, DISP is caused to execute control for connecting the ISDN line 87. When connection in the ISDN line 87 terminates, the transmission processing/reception processing of picture data/ sound data are executed between the audio telephone system 41 and the audio telephone system 41', and the audio telephone communicating picture is simultaneously displayed. |
