| 摘要 |
PURPOSE:To give an answer only to the calling subscriber that the receiver side expects, by sending the telephone number or the recognition number of the calling subscriber to the receiver side through the trunk line and giving an answer only to the calling subscriber that the receiver side has decided previously. CONSTITUTION:The telephone number of a calling subscriber that is sent to the receiver side through the trunk line 1 is detected at the telephone number detecting part 5 and then taken into the telephone number memory part 8. The telephone number stored temporarily in the part 8 is sent to the telephone number display part 7 for display and at the same time sent to the telephone number comparing part 11. On the other hand, the reserved telephone number, which is stored in the reserved telephone number memory part 10 via the reserved telephone number input part 9 in order to give an answer only to the calling subscriber that the receiver side expects is sent to the other side of the part 11. After confirmation of a coincidence between the telephone numbers, the confirmation signal is sent to the control part 12. Then the switch 13 that gives a short circuit across the ringer sound volume adjuster 3 is opened to increase the sound volume of ringer. |
