- 1-line telephone status indicator powered from a 3V battery (PDF)
- 4-line telephone status indicator that is polarity independent (PDF)
- 8-line intercom system using 89C51 microcontroller
- 900MHz cordless phone bug
- Assorted telephone circuits (ring generator, in-use indicator, audio interface)
- Audio Visual Indicator for Telephones
- Caller ID decoder (requied Postscript file viewer and/or Ordcad schematic capture)
- Cellular Phone calling Detector
- Cellular Phone calling Detector
- Cellular Phone calling Detector
- Cellular Phone calling detector (detects RF field)
- Cordless phone backup power source using LM317L
- Cut Phone Line Detector
- Cut Phone Line Detector
- Cut Phone Line Detector
- Cut phone line detector
- Cut telephone line detector
- Detecting a telephone ring signal
- Digisound ring modulator
- Digital/Standard Phone Line Tester
- DSL / ADSL phone line filter
- FM Telephone Bug
- FM Telephone Bug
- FM Telephone Bug
- FM telephone line bug transmitter (88MHz to 94MHz)
- Greek telecard reader
- High Quality Intercom using LM380 amplifier IC
- Hold function for Telephone
- Home made PBX / PABX
- Incoming call indicator (ZIP file)
- Infinity bug for remote telephone surveillance
- Isolated Telephone Interface
- Isolated Telephone Interface (phone tap) for tape recorder, PC sound card etc
- Line in use indicator that handles two independent phone lines (PDF)
- Low cost intercom using transistors
- Off line Telephone tester
- Phone "Hold" With Music
- Phone Broadcaster / telehone bugging device circuit diagram
- Phone Busy Indicator
- Phone Busy Indicator
- Phone Busy Indicator
- Phone In Use Indicator circuit diagram
- Phone in-use (manually activated)
- Phone In-Use Light
- Phone line in use indicator
- Phone line indicator
- Phone line to audio interface
- Phone Off-Hook Indicator using CD4049 hex inverter
- 'phone rang' indicator light
- Phone ring circuit schematic using a piezo buzzer for sound output
- Phone to audio interface for SSI202 input
- Phone-In-Use indicator
- Remote Telephone Bell Ringer
- Ringing Phone Light Flasher
- Ringing Phone Light Flasher
- Ringing Phone Light Flasher using optocoupler and relay
- Simple alarm with telephone dialler interface
- Simple circuit to connect telephone equipment to audio mixer
- Simple intercom
- Simple Phone Tap
- Simple Phone Tap Circuit
- Simple Phone Tap circuit diagram
- Simple Skype VoIP analog adapter
- Simple speakerphone
- Simple telephone line tap for intercepting telephone calls
- Smart Phone light
- Soft Musical Telephone Ringer
- Soft musical telephone ringer
- Talking phone dial monitor (PDF)
- Taxi phone automatic dialler
- Telephone amplifier
- Telephone amplifier
- Telephone auto-dialler (useful for an alarm dialler)
- Telephone Hold Button
- Telephone Hold Button
- Telephone Hold Button circuit
- Telephone in use light
- Telephone Line Filter / Protector
- Telephone Line Monitor
- Telephone line monitor
- Telephone line monitor
- Telephone line simulator
- Telephone music on hold interface
- Telephone privacy adapter
- Telephone Record Control using 2N4360, 2N2222 and 2N2102
- Telephone Recorder
- Telephone Recorder
- Telephone recorder to record phone conversations automatically
- Telephone ringing circuits
- The 89C51 PABX
- The Link 4+0 - Internal Intercom (Doesn't offer external line access)
- The Link A2B+1 (the Link Telephone Intercom - DTMF version)
- The Original 2 Phone Intercom Link Design
- Universal telephone hold
- Use old telephones as an intercom
- Wireless Telephone Bug
About Me
- B.Tech Live projects for ECE,EEE,EIE,ICE
- This site will be verymuch useful for students studying electronics,Electrical,Instrumentation engineering. The site showcases many links from around the web with good stuff related to electronics. Electronics hobbyists can find this a good place to start.Many simple circuits that you can build from scratch available on this site.Engineering Students of JNTU,AU,KU,OU,SRM,NU can be benifitted with this resource. Any concerns please email me technokishore@gmail.com
Telephone & Intercom related schematics
Posted By B.Tech Live projects for ECE,EEE,EIE,ICE
Sunday, April 4, 2010
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Polite Notice
B.tech Live projects is the platform for everyone who are studying Electronics Engineering. Note that all these links are external and we cannot provide support on the circuits or offer any guarantees to their accuracy. Also note that some of the circuits are illegal to operate in most countries, please check your local regulatory bodies if concerned. Other circuits are dangerous to construct and should not be attempted by the inexperienced.
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