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Miscellaneous telephone circuit diagrams
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December 2, 2010
This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold. [more]
November 30, 2010
The normal telephone bell, at times (specially during night when one does not want to be disturbed), appears to be quite irritating. The circuit shown here converts the loud sounding bell into a soft and... [more]
November 30, 2010
You are asking how to connect up some lights so that when the phone rings, they flash. This is very useful in a situation were there is lots of noise and it is impossable to... [more]
November 15, 2010
This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED. [more]
November 9, 2010
While talking to a distant subscriber on telephone, quite often we feel frustrated when the voice of the distant subscriber is so faint that it is barely intelligible. To overcome the problem, circuit of an... [more]
September 27, 2010
This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED. The device must be... [more]
circuit from:http://www.extremecircuits.net/2009/12/cellular-phone-calling-detector-circuit.html
September 27, 2010
If you are lucky enough to have a big house, a large garden, and small children, this project just might interest you. It’s actually a telephone ringer capable of making any mains-powered device work from... [more]
circuit from:http://www.extremecircuits.net/2010/05/telephone-ringer.html
September 26, 2010
A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now... [more]
circuit from:http://www.extremecircuits.net/2010/05/protection-for-telephone-line.html
July 2, 2010
Although a hold feature is standard on most new phones, a lot of us still use the origional bell phones. Those of us that require a hold feature will find this circuit very useful. It... [more]
April 28, 2010
Audio from a telephone line can be obtained using a transformer and capacitor to isolate the line from external equipment. A non-polarized capacitor is placed in series with the transformer line connection to prevent DC... [more]
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