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8-Channel DTMF Link: Encoder – Circuit Schematic
8-Channel DTMF Link: Encoder
The signal is encoded as a pair of sine waves, ensuring that no frequency is a multiple of the other and the sum and difference between two frequencies does not...
U4076B Three-tone Ringer Telephone Sets – Circuit Schematic
U4076B Three-tone Ringer Telephone Sets
The three-tone ringing integrated circuit U4076B in conjunction with a piezo transducer or loudspeaker replaces the normal electromechanical telephone bell. It ...
LA7051 Audio Signal Processor For Uhf Band Rf Modulator – Circuit Schematic
LA7051 Audio Signal Processor For Uhf Band Rf Modulator
The LA7051 is a video, Audio signal processor IC for UHF band RF Modulator It performs the functions of Audio FM Modulator video clamp circuit, white clip circu...
telephone transmitter circuit – Circuit Schematic
telephone transmitter circuit
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Commander – Circuit Schematic
Commander
Commander allows you to control your Alinco, Elecraft, Flexradio, Icom, JRC, Kachina, Kenwood, TenTec, or Yaesu radio from a PC running Windows 95, 98, NT, 2000...
Spy Telephone – Circuit Schematic
Spy Telephone
This FM spy telephone circuit is mounted serial with the phone line. When is signal on the wires this transmitter will radiate airwaves thru the wires which act...
Off Line Telephone Tester – Circuit Schematic
Off Line Telephone Tester
A circuit of an off-line telephone tester which does not require any telephone line for testing a telephone instrument. The circuit is so simple that it can be ...
The Link A2B+1 (the Link Telephone Intercom - DTMF version)s – Circuit Schematic
The Link A2B+1 (the Link Telephone Intercom - DTMF version)s
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Telephone line monitors – Circuit Schematic
Telephone line monitors
This nifty little circuit lets you record your phone conversations automatically. The device connects to the phone line, your tape recorder`s microphone input, ...
Telephone Hold Buttons – Circuit Schematic
Telephone Hold Buttons
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Phone Busy Indicators – Circuit Schematic
Phone Busy Indicators
It signals that the phone is in use by lighting a red LED. When the phone is not in use, a green LED is lit. It needs no external power and can be connected any...
FM Telephone Bugs – Circuit Schematic
FM Telephone Bugs
Small telephone bug. Listen telephone line on your FM receiver. It is self powered. Small part count. Circuit diagram, schematics, electronics project.....
Privacy Telephone Intercom – Circuit Schematic
Privacy Telephone Intercom
The circuit you are about to see is the culmination of some effort at improving the basic Link intercom design. You may think that pulse dialing is `old hat` no...
The Original 2 Phone Link= – Circuit Schematic
The Original 2 Phone Link=
This is the circuit that sparked off all the other Link Telephone Intercom designs. Originally designed back in 1996 with heavy duty relays and their contact ba...
GPS reference clock NTP server with Gentoo – Circuit Schematic
GPS reference clock NTP server with Gentoo
An L7805 provides a 5v rail. The input and output of the reg is bridged by a 470 F and a 10 F capacitor respectively to try and smooth things out a bit. The 5v ...
Design Caller ID using DTMF decoder MT8870 – Circuit Schematic
Design Caller ID using DTMF decoder MT8870
It`s very simple circuit using DTMF decoder MT8870 (or CM8870). As shown in the circuit, u`ll receive an interrupt ( if NAND output is connected to INT of the m...
Dean Forest Railway Telecoms – Circuit Schematic
Dean Forest Railway Telecoms
Each line key has three positions. Centralised it connects the line circuit to line to await a call. Downwards (KK) it operates a K relay which switches the lin...
Xrt5683 Operation At 10.1mbps – Circuit Schematic
Xrt5683 Operation At 10.1mbps
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TS2418 Telephone Tone Ringer With Bridge Diode – Circuit Schematic
TS2418 Telephone Tone Ringer With Bridge Diode
The TS4956 is a complete Audio system device with three dedicated outputs, one stereo Headphone one loudspeaker drive and one mono line for a hands-free set. Th...
TEA1069 TEA1069; TEA1069A Versatile Speech/dialler/ringer With Music-on-hold – Circuit Schematic
TEA1069 TEA1069; TEA1069A Versatile Speech/dialler/ringer With Music-on-hold
The TEA5711 is a high performance Bimos IC for use in AM/FM stereo Radios All necessary functions are integrated: from AM and FM front-end to AM detector and FM...