| 摘要 |
PURPOSE:To prevent the occupancy of a telephone circuit for a long period of time by measuring the time with a control microprocessor and using a timer interruption generating means to disconnect the telephone circuit after deciding that a key input calling an information center is not delivered for a fixed period of time. CONSTITUTION:A microprocessor 7 is always counting the information supplied from a timer interruption generating circuit 6 and calculates the lapse of time while a telephone circuit is occupied by a character graphic display device. At the same time, the processor 7 monitors the lapse of time and decides that the circuit is not used if no key input is given for several seconds when the time set previously elapses from the end of the transmission of information and the last key input. Then the processor 7 controls a circuit controller through a drive circuit 5 and disconnects the telephone circuit. |
