DATA TRANSMISSON SYSTEM OF SUBSCRIBER TELEPHONE CIRCUIT

PURPOSE:To perform originating incoming at a terminal for the automatic inspection of a water-work meter, etc., and to obtain a simplified, high-reliability device, by using a common data transmission and reception sequence between the terminal and a center side. CONSTITUTION:A CPU1 controls a center network controller 3, which has a transmitting function for dial information necessary for a connection between a special trunk 8 and a terminal network controller 10, a transmitting and receiving function for various control signals, a receiving function for a call signal of 16Hz for terminal origination, a transmitting and receiving function for various control signals, and a modulating and demodulating function for data communication. Further, the trunk 8, fitted to an exchange 7, serves as a call side for a center side device or calling side for a terminal device 13 during center origination and has a no-ringing connection function for the device 10. Further, a common data transmission and reception sequence is employed after the terminal and center side are connected mutually.