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2.45GHz RF Signal Detector - This passive RF indicator is made from a few
simple parts. A 100uA moving coil meter is used to display the relative
intensity of the RF signal. This circuit can be used with some cell phones and many
cordless telephones. (added 7/06) …. [Hobby Corner Circuit by Dave Johnson] |
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3.5 mm or 6.25 mm Stereo Telephone plug - ….(electronic schematic added
03/08) |
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3.5 mm or 6.5 mm Mono Telephone plug - ….(Circuit design added 03/08)
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300 baud modem circuit schematic - La plupart des modems de type Baycom
comportent des circuits qui sont devenus difficiles à trouver, surtout si l'on veut
pratiquer le packet à 300 bauds. Une alternative consiste à utiliser plusieurs
circuits intégrés qui existent encore, et qui, finalement, reviennent moins cher.
Cependant....(circuit added 04/05/06) |
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4 Line Telephone Line Status Indicator - Many home businesses use multiple
phone lines. This circuit gives you a visual indication when a line is in
operation. The two AA battery cells should provide enough power for about one year of
operation.... [Designed by David A. Johnson] |
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5 Band Graphic Equalizer using a Single IC/Chip - This circuit uses a single
chip, IC BA3812L for realizing a 5 band graphic equalizer for use in hi-fi audio
systems. BA3812L is a five-point graphic equalizer that has all required
functions integrated onto one IC. IC is comprised of five tone control
circuits and input and output buffer Amplifiers.…. (added 10/05) |
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56K RF Modem - (circuit / schematic added 6/05) |
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60-mA current-source feeds telecomm lines - 12/18/97 EDN-Design Ideas An
isolated 60-mA current source provides 120V of compliance for use in telecommunication
interfaces (Figure 1). Constant-current line feed provides dc power for downstream
circuitry independent of line length and provides inherent short-circuit protection.
The key to isolated.... [Design Idea by Kurk Mathews, Linear Technology Corp,
Milpitas, CA] |
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8 Line Intercommunication using 89c51 - ….... [Site is under construction
right now] |
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9-Line Telephone Sharer - .... |
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9-pin null modem cable - Circuit only, no circuit description included….
[Tony van Roon's circuit] |
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ADSL Modems that Use the LT1886 as a Line Driver Yield Long Reach & Fast Data Rates
- DN240 Design Notes (Linear Technology) (app note added 1/06)
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Advances in High Speed Design in Dispersively Attenuating Environments Circuit Boards
& Cables - ....deals with advances made in methods for....aiding the design
and analysis of high performance digital....through dipersively attenuating paths.
Agilent Application Note 2002-04-10 (app note added 06/06/06) |
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Alarm Phone Dialer with MT8880 & PIC 16F84A - Just hook this Alarm Phone
Dialer up to something you would like to monitor, for example, a high water alarm, low
temperature alarm, back window, garage door, etc. When the system is activated it will
call a number of programmed numbers to let you know the alarm has been activated.
This would be great to get alerts of alarm conditions from your home when you are at
work. The microcontroller code is provided on the site. ….(design added 11/08)
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AN-1034: An Optimized DCE Interface for V.34 Modems using the DS8933 & DS8934 Line
Drivers & Receivers - National Semiconductor Application Note (app
note added 2/06) |
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AN106 Quick CS6420 Speakerphone Interface - (app note added 6/07)
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AN-214: Ground Rules for High Speed Circuits - AN-214 Analog Devices
Application Notes....[App Note]Layout and Wiring Are Critical in Video Converter
Circuits. |
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AN237: TCP/IP Library Programmer's Guide - Silicon Labs Application
Notes....[App Note] |
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AN-347: Shielding & Guarding - AN-347 Analog Devices Application
Notes....[App Note]How to Exclude Interference-Type Noise. What to do and Why to do
it-A Rational Approach |
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AN-444: Single Chip Modem Provides Low-Cost Data Communication - National
Semiconductor Application Note (app note added 2/06) |
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AN-466: Improving the Performance of a High Speed PBX Backplane - National
Semiconductor Application Note (app note added 2/06) |
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AN-521: Dual Tone Multiple Frequency DTMF - National Semiconductor
Application Note (app note added 2/06) |
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AN-666: DTMF Generation with 3.58 MHz Crystal - National Semiconductor
Application Note (app note added 2/06) |
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AN-772: A Design & Manufacturing Guide for the Lead Frame Chip Scale Package -
AN-772 Analog Devices Application Notes....[App Note] |
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AN833: Microchip TCP/IP Stack Application Note - Microchip Application Note
Published 6-Mar-02 (app note added 2/06) |
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AN854: Connecting a Picmicro® MicroController to a Standard Analog Telephone Line
- Microchip Application Note Published 21-Aug-02....[App Note] |
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AN-D27: DMOS Devices for Telecommunications - Supertex Semiconductors
(app note added 2/06) |
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Assorted telephone circuits - several circuits here, spend some time and
view each of them |
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Audio Graphic Equaliser - Simple 7 band eqalizer (diagram added 2/07)
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Audio Visual Indicator for Telephones - Many a times one needs an extra
telephone ringer in an ad joining room to know if re is an incoming call. For example,
if telephone is installed in drawing room you may need an extra ringer in
bedroom. All that needs to be done is to connect given circuit in parallel with
existing telephone lines using twin flexible wires. This circuit does not
require any external power source....(added 10/05) |
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Audio Visual Ringer - Many a times one needs an extra telephone ringer in an
adjoining room to know if re is an incoming call. For example, if telephone is
installed in drawing room you may need an extra ringer in bedroom. All
that needs to be done is to connect given circuit in parallel with
existing telephone lines using twin flexible wires. This circuit does not
require any external power....(added 10/05) |
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