| 摘要 |
PURPOSE:To attain defence of a malicious call by informing an incoming call when a converted sender subscriber number and a registered opposite number are coincident. CONSTITUTION:When an incoming call comes to a telephone set, an exchange sends a sender subscriber number in a form of a PB signal at a pause time of a call signal sent from the exchange to a subscriber circuit L, the signal is received by a PB signal reception circuit 1 and sent to a central processing unit 6 as a data subject to code conversion. The central processing unit 6 reads a registered incoming reception opposite number from a memory section 3 and when the number is coincident with the sender subscriber number to be received, a drive circuit 4 is started to ring a bell for informing an incoming call.
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