| 摘要 |
PURPOSE:To prevent erroneous operation by identifying whether or not it is necessary to send a subscriber number, sending one side frequency only out of multi-frequency signals and sending the second dial tone, when a starting signal to show that sending is unnecessary is inputted. CONSTITUTION:A discriminator 16 discriminates whether or not the special number is a number necessary to send an identifying number, a starting signal different in accordance with the necessity, for example, a starting signal having a different polarity or a frequency is sent through a special outgoing trunk 18 an an exchanging switch network 13 to an identifying number sending device 12. When the starting signal from the identifying number sending device 12 shows that the sending of the identifying number is not necessary, only one signal of the frequency out of multi-frequency signals is sent. The high-order station to receive the signal through the exchanging switch network 13 and the special outgoing trunk 18 neglects the signal since the signal is not a regular number, a signal sound sending device 19 in a register sender 15 responds to the signal, and after completion, the signal like the dial tone to instruct to execute the next dial is sent to the subscriber.
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