| 摘要 |
PURPOSE:To allow a specific speeker alone to make toll transmission by discriminating an acoustic input from a user. CONSTITUTION:When a user off-hooks, a hook switch 14 is actuated, and a DC loop is formed in the following order; an exchanging device-input/output ter and allowing sound recording an applicable audible signal on a silent section tape. CONSTITUTION:When output from a VCAC detection circuit 15 is detected during sound recording a message ICM transmitted from a calling party, that is, a silent condition is detected, a control circuit 1 actuates a two second timer 16, and after the lapse of two seconds, the timer output drives an oscillator 17 to send out a specific audible signal. The audible signal is transmitted to a head 14 via an amplifier 13 and written on an ICM tape. When an acoustic input more than two seconds is suspended during ICM sound recording, the ICM tape becomes a sound recording conditionion of the contact point 40 of the relay 4 by a specific number detection circuit 5 and output the signal to the circuit 6. Dial signals after the second figure are sent out to the exchanging device side by an impulse contact point 13. |
