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Digital Telemetry with ATMega8 – Circuit Schematic
Digital Telemetry with ATMega8
The ATmega8 microcontroller-based Low-Cost Telemetry Device (LTD) is an efficient telemetry keyer. The LTD measures the voltage levels of up to four analog chan...
DTMF Phone Dialer with PIC16F690 and NTE1690 – Circuit Schematic
DTMF Phone Dialer with PIC16F690 and NTE1690
The circuit uses a NTE1690 DTMF dialer chip and a PIC16F690 microcontroller. Because this is an IP phone and I cannot just send the DTMF tones over the line, th...
Bi-directional intercom system – Circuit Schematic
Bi-directional intercom system
This is a very small telephone exchange attached only two ordinary Tele phones. Fully bi-directional facility with an intercom system. When a phone is in off ho...
Advanced Telephone Intercom – Circuit Schematic
Advanced Telephone Intercom
In order to achieve a status between two levels of switching for two calls at the same time, you must first establish privacy on each call. Otherwise, you will ...
Telephone Intercom - DTMF – Circuit Schematic
Telephone Intercom - DTMF
This version of the Link uses DTMF tones for dialling both internally between handsets, and externally for outside calls. Remember, in some countries, it is ILL...
Telephone Intercom – Circuit Schematic
Telephone Intercom
The Link circuitry is simple and efficient, employing just two ICs, half a dozen transistors, and a handful of garden variety components. It all runs on 12 volt...
Busy Telephone line Indicator – Circuit Schematic
Busy Telephone line Indicator
Have you ever been using the modem or fax and someone else picks up the phone, breaking the connection? Well, this simple circuit should put an end to that. It ...
Busy Telephone line Indicator – Circuit Schematic
Busy Telephone line Indicator
Have you ever been using the modem or fax and someone else picks up the phone, breaking the connection? Well, this simple circuit should put an end to that. It ...
Phone line indicator using BF256B – Circuit Schematic
Phone line indicator using BF256B
With this circuit can determine whether any of the phones of the same line is busy (it's up the handset), with the help of a LED.To circuit has no measurable ef...
Phone line indicator using BF256B – Circuit Schematic
Phone line indicator using BF256B
With this circuit can determine whether any of the phones of the same line is busy (it's up the handset), with the help of a LED.To circuit has no measurable ef...
GSM Automatic Meter Reading – Circuit Schematic
GSM Automatic Meter Reading
GSM based Automatic meter reading, or AMR, is the technology of automatically collecting data from energy meter and transferring that data to a central database...
Electronics Telephone Talking Circuit – Circuit Schematic
Electronics Telephone Talking Circuit
This is the basis of electronics telephone sets. You can use it to replace the talking circuit of an old telephone set with new design, better noise rejection a...
SMS through Telephone with AT89S8252 – Circuit Schematic
SMS through Telephone with AT89S8252
The main objective of this system is to transmit message or text through ordinary Land Line Telephone from one end (source) to another end (designation). This i...
Telephone motor Controller – Circuit Schematic
Telephone motor Controller
This Project is used to control a single phase Motor from any where in the world through the telephone. The circuit consists of a DTMF tone detector and a power...
Two Line Intercom circuit – Circuit Schematic
Two Line Intercom circuit
This project is used as an electronic private exchange. It has two telephones, which have the intercom facility, and they can be connected to the telephone line...
Interactive Voice Response System – Circuit Schematic
Interactive Voice Response System
Now-a-days every institution needs automation. As a part of college automation, we have decided to do a project Voice Interactive System for College Automation....
PAL Colour Encoder (TEA2000-V1)
A PAL color encoder and video summer which requires just composite sync and composite blanking inputs, and a 6-bit binary coded input giving the color informati...
Isolated Telephone Interface – Circuit Schematic
Isolated Telephone Interface
This circuit allows you to record audio from a telephone line into a tape recorder or computer soundcard. Most of the parts for this circuit can be scrounged fr...
Cellular Phone Detector – Circuit Schematic
Cellular Phone Detector
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 flashin...
Two line intercom – Circuit Schematic
Two line intercom
The circuit presented here can be used for connecting two telephones in parallel and also as a 2-line intercom. Usually a single telephone is connected to a te...