Telephony DTMF Circuits


Posted on Feb 6, 2014

This circuit is able to handle nine independent telephones (using a single telephone line pair) located at nine different locations, PDF 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.


Telephony DTMF Circuits
Click here to download the full size of the above Circuit.

Couple modem equipped PCs for gaming or testing of communications software 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 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 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 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 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...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Magnetic Card Reader with PIC12F675
    Digital Compass
    Non inverting audio amplifier
    Lighting Control
    Simple Audio Mixer Circuits
    transformer Single pole AC to DC conversion circuit
    strobe light controller
    pendulum controlled clock
    5000W ultra-light high-power amplifier without switching-mode power supply
    High-performance dual-band wireless microphone receiver circuit diagram
    XTR101 bridge input voltage excitation circuit diagram



    Top