| 摘要 |
PURPOSE:To display a telephone number of a caller on a display device attached to a telephone set at incoming side during alarming, by detecting whether a handset is taken up on or not. CONSTITUTION:When a handset of a TEL is taken up for dialing, contacts HS1, HS2, HS3 interlocked with the hook switch are selected to opposite side as shown in Figure. Further, a terminal 2 of an IC-85 is at H, a multivibrator consisting of ICs 85 and 86 is operated and the output is inputted to a data input terminal DI of a hexadecimal counter IC-88, multidigit display 10 and a printer 11. Further, when the number of count of the IC-88 reaches 11, the oscillation of the said multivibrator is stopped. When a caller dials the telephone number of a called party, the said dial pulse is applied to a one shot pulse generating circuit 9 and displayed on a display device 10. |
