| 摘要 |
PURPOSE:To use the same transmission system to both voice communication and data communication by constituting that a data terminal device is connected selectively to a data modulating and demodulating device so as to use the data modulating and demodulating device in common for utilizing effectively the affinity of a digital exchange and the data terminal device. CONSTITUTION:A data terminal adaptor 350 converts a signal and control information from a data terminal device 340 into a digital signal of the same information amont as the voice signal in 64 kbps and transmits the result to switch network 300 of the exchange. The exchange side transmits the digital signal in 64 kbps to the data modulating and demodulating adaptor 320 after receiving said signal. The adaptor 320 converts the signal transmitted via a path from the digital signal in 64 kbps entirely opposite to the processing by the data terminal adaptor 350 and transmits the result to a data modulating and demodulating device 330. The data modulating and demodulating device 330 converts the signal information into a modulating signal in the voice frequency band, returns the result to the adaptor 320, where the signal is converted into a PCM code in 64 kbps and transmitted to a switch network 300. |
