Automatic telephone call recording circuit
Source: InternetPublisher:无人共我 Keywords: Power communication power Updated: 2020/02/28
![Automatic telephone call recording circuit](http://www.eeworld.com.cn/circuit/upload/faa78b7411bf4d05f4baff1bc39ea4b2/038497e8ac4b0552830642dc18119f36.gif)
DC voltage on telephone lines is currently typically around 45 to 50V, with 6V on-hook and off-hook. This circuit uses a step-down activated relay. Relay controls tape recorder. Audio is via network to tape microphone input.
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