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DTR Powered EchoLink Interface - "Tiny Echo"

Advanced, PIC 16F84A EchoLink Interface -"Fox Echo"

Audio AGC add-on Card for Foxecho-K7




 PIC 16F84A Micro Controller EchoLink* Interface






Click to enlarge


 Click to enlarge

Revision: 0808



Fox Delta: Foxecho-K7 Echolink Interface



PIC16F84A Micro Controller EchoLink* Interface is designed to achieve some of the following points of Interest to Radio Amateurs:



Real RS232 signals
100% Galvanic Separation
Plug-in Tone & AGC module (option)
COR (Positive or Negative logic selectable)
Hardware DTMF decoding 
Muting (automatic) of receiver audio
Adjustable receiver and transmitter audio levels
Power status, DTMF, PTT and COR LED's
Uses a PIC16F84A 
DIN 5 Front Panel Connector for easy interface to Rig
Transceiver connection has “HT” Header for portables
No relays. Uses HFE4053 Analog Switches.
12cm x 7cm, Double Sided PTH Board.
Usable for other digital modes like PSK31
A true homebrew project, you can build.

Foxecho-K7 interface uses an MT8870 DTMF Decoder and a PIC16F84A. Uses two 4N33 Opto Couplers and two transformers to achieve 100% isolation between transceiver and your PC.

An AGC add-on card is available to effectively control receive audio level and tone.

* EchoLink is a registered trademark of  Synergenics, LLC

Picture of the Completed EchoLink* Interface

Click to enlarge


 FoxEcho-K7 Doc & Firmware
Technical Info Doc Fox Echo Schematic & Parts List
Transceiver Connection to DIN5 and Header Details Fox Echo Schematic & Parts List
Kit Parts List Fox Echo Schematic & Parts List
Foxecho-k7 Sysop Config. Document Fox Echo Schematic & Parts List
Foxecho-k7 Mic & Header Setup Fox Echo Schematic & Parts List

Schematic JPG
FoxEcho-K7 Schematic & Parts List

Schematic of the Isolated components JPG JPG
 Project Resources & Download
PIC16F84A Firmware

 Want to make your own PCBs?

FE-K7 RS274X Gerber Files

Andreas, DL5MGD's Echolink Webpage Fox Echo Schematic
DL5MGD PIC16F84A Firmware
Old Version Documents

BUY FROM 2CO       

FoxEcho-K7 Kit (without Metal Case)


Kit Packing List
PCBs may be available from our shop at foxdelta.net Visit School Project Shop


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