Telephone Related
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SIMPLE RGB LED LED EFFECT CIRCUIT Schematic Circuit Diagram
The circuit board was tested with a single piece rgb strip led on the ne555 and 74393 integrators. If you…
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Phone Ring Repeater Schematic Circuit Diagram
Even though cordless phones have invaded our homes and offices, you don’t always have them at hand, and as their…
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Telephone Ringer Schematic Circuit Diagram
If you are lucky enough to have a big house, a large garden, and small children, this project just might…
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Telephone Line Indicator Schematic Circuit Diagram
Many ‘busy’ indicators for use in telephone systems present undesirable loading of the telephone line. Some circuits are very simple…
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Telephone Line Watchdog Schematic Circuit Diagram
Circuits have been published on earlier occasions that keep an eye on the telephone line. This simple circuit does it…
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8-channel DTMF Link: Encoder Schematic Circuit Diagram
Generated millions of times every day by our telephone keypads, the eight DTMF frequencies were chosen so that the harmonics…
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Wire Tracer (Transmitter) Schematic Circuit Diagram
The circuit depicted here forms one half of a device that will prove extremely handy when tracing the path of…
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Telephone monitor
It is sometimes necessary to make a telephone conversation audible to more than one person at either end or to make…
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Privacy phone
Undesired listening-in to phone conversations may be prevented by the present circuit, which requires only two components to protect a…
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Telephone-operated night light
Since in some countries, it may be illegal to connect the circuit to the public telephone network, to check with…
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