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Telephone: Telephone In-Use Circuit & Useful Telephone Circuits

Phone In-Use Electronic Circuits and Other Cool Telephone Circuits.

This bunch of telephone circuits will allow you to do lots of cool things with telephones. Detect when a phone line is in-use, when there is an incoming call, track outbound/dialed telephone numbers, etc.

5 Useful Telephone System Circuits
0 Comments - in Telephone
Features a telephone ring generators, phone line in-use indicators and an audio interface circuit.
Visual and Audible Alert For Incoming Telephone Call Circuit
0 Comments - in Telephone
Electronic circuit that connects to phone line and produces and flashing LED and audible sound when there is an incoming call.
Portable Cell-Phone Battery Charger
2 Comments - in Telephone
A very clever portable cell phone battery charger that uses 8x1.5 AA cells (batteries) to charge cell-phone / mobile phone batteries while mobile. No more need for a mains outlet!
Photo: Electronic Telephone Kit Electronic Telephone Kit
Learn how a telephone works. Comes complete with all parts and manual. Has the latest features such as automatic redial, mute and flashing neon lights when ringing. The clear plastic case allows you to show your friends your accomplishment.
Mobile Phone Incoming Call Detector
5 Comments - in Telephone
A simple circuit that flashes an LED when a cell phone has an incoming call. Uses a coil to pick-up the signal emitted during an incoming call event. Cell phone call detector.
Photo: Outgoing Phone Number Logger Kit Outgoing Phone Number Logger Kit
Recorder all outgoing dialed numbers on your phone with this electronic kit.
Photo: Cellular Phone Sound Effects Cellular Phone Sound Effects
Easy to build sound effect generator kits, inludes several different sounds and tunes.
Photo: Phone Pickup Suction Cup Electronic Kits Phone Pickup Suction Cup Electronic Kits
No electrical connection to the telephone is required, attach a suction cup to the hand set an turn on the amplifier. This project permits group listening to phone calls. You can also use it to monitor any other oscillating electrical field. Dual IC's pro
Photo: DTMF Tone Grabber Kit DTMF Tone Grabber Kit
The kit will detect DTMF tones from a telephone line or via an onboard microphone and display them on a 16 character, single line display.