Telephone circuits 
related topic: Telephony |
| 2 line phone
status indicator
pdf file |
|
9-line telephone sharer This circuit is able to handle nine independent
telephones (using a single telephone line pair) located at nine different
locations,
pdf file |
|
Bidirectional
telephone line simulator without using telephone lines, couple, test and demonstrate all types of telephone equipment such as: answering machine, modem, fax, call recorder, call diverter, extension ringer, telephone ring booster, security autodialler etc. Couple modem equipped PCs for gaming or testing of communications
software |
| Build
your own inductive telephone tap an inductive telephone tap that will allow
us to listen to telephone conversations nearly undetectably |
|
Cordless phone frequencies
cordless phones are still analogue and use the frequency from 30-50MHz. The
signal is FM-modulated and can easy be picked up with any FM-receiver |
|
Cut Phone Line Detector
schematic of a circuit to detect cut phone lines |
|
DTMF Coding and
Decoding Module
Two chips are adopted for DTMF coding and decoding
respectively |
| DTMF decoder circuit |
|
DTMF Phone Dialer |
|
DTMF Generation with a 3.58 MHz Crystal
DTMF generation consists of
selecting and combining two audio tone frequencies associated with the rows (low
band frequency) and columns (high band frequency) of a pushbutton touch tone
telephone keypad, pdf file |
| DTMF generator/decoder
Dual-tone-multi-frequency (DTMF, also known as touch-tone) are the audible sounds you hear when you press keys on your phone |
|
DTMF
Generator The MV5089 is fabricated using ISO-CMOS high density technology
and offers low power and wide voltage operation. An inexpensive 3.58MHz TV
crystal completes the reference oscillator. From this frequency are derived 8
different sinusoidal frequencies which, when appropriately mixed, provide
Dual-Tone Multi-Frequency (DTMF) tones, pdf file |
|
DTMF Remote Control
DTMF Remote control – A software DTMF decoder for PIC 16F87X |
|
DTMF
tone decoder with LCD display
this project displays telephone numbers
decoded from tones. A microphone picks up the tones, a preamplifier boosts the
signals, an SSI-202 DTMF chip decodes the tones, a Basic Stamp acts as an
interface to an LCD display and also provides "RS-232" serial output |
|
DTMF - Decoding with a 1-bit A/D converter
The purpose of DTMF decoding is to detect sinusoidal signals in the presence of
noise |
| DTMF
generator/decoder |
|
DTMF
microphone monitor telephone numbers (control signals) off the air by
using your PC game port to input the signals |
| Caller ID display service
en Français |
|
Démodulateur
DTMF CD22202, en Français |
|
Encodeur DTMF
MK5380, en Français |
|
FM Telephone Bug
a simple transmitter that when connected to a phone line, will transmit anything
on that line (execpt the dial tone) to any FM radio. The frequency can be tuned
from 88 to about 94Mhz and the range is about 200 feet |
|
Generating DTMF tones using computer soundcard
DTMF Tone Generator Applet |
|
Phone amplifier telephone amplifier circuit |
|
Phone in use indicator |
|
PLL tone
decoder IC
The BA1604 and BA1604F are tone decoder ICs that enable the
frequency to be selected in precise detail, using a PLL system. These ICs are configured of a PLL circuit, a detection circuit, a
voltage comparator circuit and an output logic drive circuit, pdf file |
|
Radio Remote Control using DTMF using
UM91214/UM91216 datasheet
and KT3170 datasheet.
The KT3170 is a complete Dual Tone Multiple Frequency (DTMF) receiver that is
fabricated by low power CMOS and the Switched-Capacitor Filter technology. |
|
Remote Telephone Ringer
This remote telephone bell ringer allows you to use a large (and loud) external
bell in place or in addition to the built in (and rather wussy) ringer in most
modern telephones |
| Smart ringing phone light to switch on a lamp when the tele- phone rings |
|
Telephone
Activated Switch |
|
Telephone
Call Counter The circuit presented here is a very useful add-on device to be
connected to the telephone lines to count and display the number of incoming
calls received in the absence of the subscriber |
|
Telephone Circuits |
|
Telephone conversation recorder enables automatic switching-on of the tape recorder when the handset is lifted |
|
Telephone in use
indicator |
|
Telephone in use
indicator |
|
Telephone Line In Use Indicator This document presents a design for an
electronic circuit which connects to a telephone line and provides a visual
indication of whether or not the line is in use, so that two or more people
sharing a line can avoid interrupting each other's voice or modem calls |
|
Telephone line audio interface circuits
How telephone works, Network
Interface in telephone, Telecom hybrid circuits for other equipments than
telephones, Audio interfaces to telephone lines, Telephone audio interfaces from
Usenet news, Audio interfaces without transformer isolation, Simple telecom
hybrid circuits, More details implementing telephone line interface, Problems in
linking telephone hybrid to audio system, Helpful tips for telephone hybrid
circuit designers, Connecting hybrids and telephone equipments, Components for
telephone line interfacing, Telephone line technical details, Telephone line
details in different countries, Interference in the telephone line signal |
|
Telephone line simulator construction project
telephone line simulator with dialtone, busy tone & ring signal |
| Telephone line status indicator
pdf file |
|
Telephone Number Display The given circuit, when connected in parallel to a
telephone, displays the number dialled from the telephone set using the DTMF
mode. This circuit can also show the number dialled from the phone of the called
party,
pdf file |
|
Telephone Ring Generator Using Switching Supply |
|
Horizontaal |
|
|
Home
|
Site Map
|
Email: support[at]karadimov.info
Last updated on:
2011-01-18
|
Copyright © 2011-2021 Educypedia.
http://educypedia.karadimov.info
|
| |
