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.
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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...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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