| 摘要 |
PURPOSE:To enable to supply the howler signal at the same time to a plurality of subscribers with small and light weight unit and low power consumption and economy, by performing the control of amplitude of howler signal with the count circuit provided corresponding to the subscribers. CONSTITUTION:When the handset of the subscriber 204 is detected for out of hook, the communication path between the subscriber 204 and the hawler signal supply source 201 is formed with the communication circuit 200. After that, the count circuit 203 starts the count of clock pulse with the instruction of the control circuit 202, and the gain of the variable gain amplifying circuit 205 is increased in response to the output of the count circuit 203. Further, the howler signal of low level fed to the variable gain amplifying circuit 25 via the exchanger circuit 200 is the hawler signal of which amplitude increases with time and it is delivered to the subscriber 204. |
