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Audio Visual
Ringer:
extra ring detector with LED and
sound output. FAIR WARNING THIS
SITE HAS ANNOYING POP UP ADS.
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Chip recorder
customizes phone ringer:
07/25/2002 EDN - Design Ideas /
Companies usually purchase one
type of telephone for all
employees, which is
understandable, especially if
they obtain a discount for
buying in quantity. One ringer
sound for everyone can pose a
problem, though, if the sound of
a ringing phone makes a dozen
people pause and look at their
telephones. Equally annoying is
the absence of a visual message
indicator.. |
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Contactless
Ringer for Telephones:
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Simple Telephone
Ring Tone Generator: |
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Soft Musical
Telephone Ringer: |
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Telephone Ring
Detector:
This is a great project to
build with a complete run down
of the circuit operation
included all parts are listed. |
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Telephone Ringer
: The
circuit requires four astable
multivibrators for its working.
Therefore two556 ICs are used
here. The IC556 contains two
Timers (similar to555 ICs) in a
single package. One can also
assemble this circuit using four
separate555 ICs. The first
multivibrator produces a
rectangular waveform
with1-second ‘low’ duration
and2-second ‘high’ duration.
This waveform is used to control
the next multivibrator that
produces another rectangular
waveform. |
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Telephone Ringer
Circuit:
Low cost, easy to build
Telephone ringer circuit.
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Telephone Ringer
using 556 Dual Timers:
Using modulated rectangular
waves of different Time periods,
The circuit presented here
produces ringing tones similar
to those produced by a
telephone. FAIR WARNING -- THIS
SITE HAS ANNOYING POP UP ADS.
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Telephone Ringer
using Timer ICs:
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Telephone Ringer
Using Timer ICs: |
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Telephone Ringing
Circuits:
how to detect ringing and how to
make phones ring
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