Home Telephone Call Recorder Wiring Diagram

Home Telephone Call Recorder Wiring Diagram

Home Telephone Call Recorder Wiring Diagram

When a call comes in, around 90V AC current at 20Hz is superimposed over the DC voltage already present in the idle line. This current is converted into DC by the diodes and fed to resistor R1, which reduces its magnitude and feeds it to LED1. The current is further reduced in magnitude by the resistor R2 and fed to the right and left channels of the stereo jack, which are connected to the AUX IN / Audio In port of a computer, in most of notebook devices, it is same between Audio Input / Mic Input.

You can built the circuit on a general-purpose PCB and enclose it in a small box. Use an RJ11 connector and stereo jack for connecting the telephone set and computer desktop/laptop (for call recording). Telephone cords can be used to connect to the phone line and the home telephone call recorder circuit. Use of a shielded cable is recommended to reduce disturbances in the recording so it we will get good audio performance from the recording. These disturbances can also be reduced by increasing the value of R2 to about 15K.

This schematic diagram come from circuit: Home Telephone Call Recorder.
Go to that page to read the explanation about above circuit design.

In the electrical sector, a schematic diagram is usually used to describe the design or model of equipment. Schematic diagrams are usually utilized for the maintenance and repair of electronic and electromechanical devices / units. Original schematics were made by hand, using standardized templates or pre-printed adhesive symbols, but nowadays Electrical CAD computer software is often used.

In electronic design automation, until the 1980s schematics were virtually the only formal representation for circuits. More lately, using the progress of computer system technology, other representations were introduced and specialized computer languages were developed, because with the explosive development of the complexity of electronic circuits, classic schematics are getting less practical. As an example, hardware description languages are indispensable for contemporary digital circuit design.

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