| 摘要 |
PURPOSE:To enhance the transmission speed by performing the A/D converting operation of a terminal processing device LCU periodically independently of the calling timing due to a central controller CCU to write digital data in a register and reading out this data at the calling timing. CONSTITUTION:In each of terminal processing devices 30-32, a received signal RXD inputted from a transmission line 20 is supplied to a synchronizing circuit 102 and is synchronized with clocks from a clock generator 107, and a clock which is synchronized in the start-stop system with clock components of the received signal RXD is given to a control circuit 101, and then, the control circuit 101 generates a control signal to read a data part of the received signal into a shift register 104 serially. Meanwhile, the address assigned to a pertinent terminal processing device is preliminarily given to an address comparing circuit 103, and this address and data read into a prescribed bit position of the shift register 104 are compared with each other by an address comparing circuit 103; and if they coincide with each other, data in the shift register 104 is transferred to an I/O buffer 105 and is given to an external device. |
