| 摘要 |
PURPOSE:To reduce the production cost of the titled circuit by constituting a tone dialor circuit and a pulse dialor circuit by a one-chip IC and using one output of both the counters at the time of a pulse dial output mode. CONSTITUTION:The IC 2 is constituted by the pulse dialor circuit 4 and the tone dialor circuit 5. When a mode alteration switch 18 is turned to an individual contact C1 on the tone dial mode side, an amplifier 19 in the IC 2 inhibits to apply an output to a voice output device on the basis of a inhibition signal from a keyboard logic 3. In the tone dial mode, an output from a row counter 10 is overlapped to an output of a column counter 11 and the overlapped signal is outputted through an amplifier 16. At that time, any output is not generated from the amplifier 19. In the pulse dial mode, the output of the counter 11 is not applied to the amplifier 16 and only an output with single frequency outputted from the amplifier 19, i.e. the output of the counter 10, is generated from the amplifier 19 as an output for generating a dial check tone in the pulse dial mode. |
