Open interface III

This revision is from 2017/01/07 17:50. You can Restore it.

Main function(Edit)

  • Completly Open source
    • Hardware and software is open (cc by-sa)
    • You can modify or build own software functionality
    • Arduino compatible chip (ATMEGA2560)
  • Operation system independent (Linux, OSX, Windows)
  • CW - complete K3NG code
    • CLI interface (telnet) or Winkey emulation
    • Memory button
    • Speed rotary encoder
    • Keying from PC com port (DTR/RTS)
  • SSB
    • Switch TX audio between Microphone (Foot switch PTT) and USB Audio (com PTT)
    • Playing audio memory from PC
  • FSK (RTTY)
    • from three source
      • Serial com port (DTR/RTS) - EXTFSK
      • Serial com port ASCII (telnet)
      • Three button memories
    • Sidetone
    • Decoding TX signal during transmit from EXTFSK
  • DIGI Modes
    • Adjust TX volume buttons
    • Adjust RX volume potentiometer
    • Isolated audio path with two transformers
  • CAT
    • Support TTL (Icom) and 232 level (Kenwood, Yaesu)
    • Own serial to USB interface with internal USB HUB
  • Band decoder
    • Support Icom, Kenwood, Yaesu CAT
    • Sniffing TRX to PC communications or automatically own request
    • Outputs
      • TTL level BCD
      • CAT on ACC connector - CI-V, Kenwood/Yaesu (need TTL/232 converter)
      • IP output (in future)
    • Galvanically isolated USB to PC - four independent ground
      • PC
      • Transceiver
      • RX audio
      • TX audio
    • micro SD card slot for future use (save config)
    • Ethernet module
    • two type PA PTT output
      • Relay - isolated but 5ms latency
      • Open collector - quick
    • ACC connector (HDMI type) with
      • Serial line
      • I2C
      • PWM
      • Analog inputs
      • Digital in/out

The hardware(Edit)

Front side(Edit)

  • 1 - PTT LED - shows the activation of one of the PTT outputs (PTT1, PTT2, PTT-SSB, PA-PTT)
  • 2 - CW LED - shows the activation of one of two CW outputs (CW1, CW-232)
  • 3 - FSK LED - shows the activation of one of two FSK outputs (FSK-Arduino, FSK-232)
  • 4 - Rotary encoder - change WPM speed in CWK and CWD MODE, and select MENU in other mode
  • 5 - SET/MEM 0 button - has functions depending on the selected MODE
    • in CWD and CWK MODE activate/deactivate Command mode
    • in FSK MODE activate transmit Memory-0
  • 6 - MEM 1-2 button - in CWD CWK FSK MODE activate two memories
  • 7 - MODE button
    • Short press MODE changes in the order |CWK >CWD |SSB >FSK |FSK |DIG
    • Long press activate MENU on LCD. In the menu, move with the rotary encoder or short press MODE button. Return change after 3 seconds without change change
  • 8 - LCD display
    • First line show
      • transmiting CW character
      • transmiting RTTY character from Arduino uppercase
      • transmiting RTTY character from PC lowercase
    • Second line show
      • First eleven characters - selected MENU
      • Second four characters - active MODE or numbers MENU
      • Last characters - show microSD card icon, if pluged
  • 9 - TX audio + button - volume UP
  • 10 - TX audio - button - volume DOWN
  • 11 - TX audio mute button - MUTE
  • 12 - RX volume potentiometer - receiving signal level

Rear side(Edit)

  • 13 - SEQUENCER output CINCH - open collector (MAX 50V/500mA)
  • 14 - PA-PTT output CINCH - dependency to rear PA PTT switch
    • Open collector (MAX 50V/500mA)
    • Relay (MAX 0,5A/125V AC, or 1A/24V DC)
  • 15 - LAN - RJ45 connector - (if Ethernet optional module installed)
  • 16 - TRX GND - M4 screw
  • 17 - MIC - Jack 3,5mm - microphone input - need preset input switch, dependency on type microphone used
    • Dynamic microphone - JP7 open
    • Electret microphone - JP7 short
  • 18 - RADIO - D-SUB 25 pin female connector Pin connection
  • 19 - PA PTT - manual switch - select what circuit will be switch PA-PTT output (CINCH and pin7 in RADIO connector)
  • 20 - PC USB - USBB type connector for PC, with isolated ground
  • 21 - FOOT SWITCH - CINCH - SSB PTT input is activated by grounding center pin
  • 22 - INTERLOCK - CINCH - input is activated by grounding center pin
  • 23 - ACC - HDMI type - by default blinded Pin connection
  • 24 - POWER - input - DC jack 2,1/5,5mm diameter to connect input power 8-18V DC (center positive)
  • 25 - PADDLE - input - activated by grounding pin

Block diagram(Edit)

Board jumper preset(Edit)

  • JP4 - DTR to CW/FSK
  • JP3 - Auto reset ON - enabling reset from serial DTR pin to Arduino
  • JP5 - Self reset ON - allows Arduino self reset from D39 output (not use)
  • JP10 - CAT Icom/Other - select between Icom CI-V and other TRX bus
  • JP7 - DC to MIC - allows DC voltagefrom TRX to your microphone
    • OPEN for dynamic microphone
    • SHORT for elecret microphone
  • P5 - CAT TTL/232 - select between two logical level
    • 5V TTL
    • +-12V RS232

Board adjust(Edit)

  • P4 - LCD contrast potentiometer
  • P2 - TX souncard AFSK volume potentiometer adjust transmit audio volume from sound card to

Internal connectors(Edit)

Hardware dependency(Edit)

Mode Source Outs
CWK - CW keyer PTT1 CW1/2 HIGH LOW
>CWD - CW daemon (PC) RTS DTR* LOW LOW
FSK - Serial ascii PTT1 Serial HIGH LOW
DIG - USB audio codec (AFSK) RTS - LOW HIGH

* JP4 jumper must be set CW or FSK

Note - character ">" shown external signal source

  • WINKEY HIGH - disable DTR/RTS
  • AFSK HIGH - switch TX audio path


  • Disconnecting the USB causes high potential (measured 80V AC) between USB-GND and GND-TRX, is usually enough:
    • Grounded case
    • Replace the power supply (not the male switched adapter without grounding pin in the drawer)



Because firmware open, LCD show dependency to use firmware.

  • First line show
    • TX signal in CW and FSK mode
    • RX sniffing decode RTTY (lowercase) during keying from PC
  • Second status line show
    • MENU
    • Source keying
    • MODE
    • microSD card icon, if insert


  • |CWK - CW Keyer by K3NG
    • WinKey/CLI emulation
    • SOURCE: USB/Serial interface
    • INPUTS: Paddle Interlock Encoder Set/Mem_buttons
    • OUTPUTS: CW1/2 PTT1/2
  • >CWD - CW Daemon
    • Keyng from PC
    • SOURCE: USB/Serial interface DTR/RTS
  • |SSB - SSB
    • SOURCE: Mic-audio
    • INPUTS: FootSwitch RTS
  • >FSK - PC FSK keying
    • RTTY keying from EXTFSK with sniffing and decode signal (lowercase) by JI3BNB / OK1HRA
    • SOURCE: USB/Serial interface, Memory0-2_button
  • |FSK generator by JI3BNB
    • generator from Serial ASCII
    • SOURCE: USB/Serial interface
    • INPUTS: ASCII, Memory0-2_button
  • |DIG - Audio FSK
    • AFSK PSK and any modes modulate fom audio
    • SOURCE: USB souncard


RADIO 25 pin D-SUB(Edit)

pin-1 in Input power 8-18V DC from Transceiver
pin-2 out CAT TXD / CI-V
pin-3 out USB4 +5V output
pin-4 USB4 -Data
pin-5 out BCD4 output TTL
pin-6 out BCD2 output TTL
pin-7 out PA PTT
pin-8 out PTT1
pin-9 out CW1
pin-10 out FSK
pin-11 out Microphone (TX)
pin-12 out TX audio
pin-13 out RX audio
pin-14 Transceiver GND
pin-15 in CAT RXD
pin-16 USB4 +Data
pin-17 TRX GND
pin-18 out BCD3 output TTL
pin-19 out BCD1 output TTL
pin-20 out PTT2
pin-21 out CW2
pin-22 out PTT Microphone
pin-23 in Interlock
pin-24 TX audio GND
pin-25 RX audio GND
shield Transceiver GND

Accessory connector (HDMI)(Edit)

WARNING - All ACC signals directly connect to ATMEGA chip without some ESD protection. Before use strongly recomended protect this lines.

ACC-1 RXD Serial3
ACC-3 TXD Serial3
ACC-4 D47
ACC-7 D30
ACC-8 D32
ACC-10 D12 PWM
ACC-11 D38
ACC-12 A2
ACC-13 A3
ACC-14 A8
ACC-17 A9
ACC-18 +5V
ACC-19 A11

ATMEGA-2560 pinout (rev 3.1415)(Edit)

Arduino pins connect to in/out Note
RX0 USB in Connect to USB/serial interface
TX0 USB out use for command CW keyer or firmware upload
D2 Interlock in pull-up external, Interrupt 0
D3 PTT-232 in pull-up external, Interrupt 1
D4 CW tone out
D5 ACC pin6 PWM
D6 LCD-D4 out
D7 LCD-D5 out
D8 LCD-D6 out
D9 LCD-D7 out
D10 Ethernet SCS out
D11 ACC pin9 PWM
D12 ACC pin10 PWM
D13 ACC pin5 PWM
TX3 ACC pin3 out + Internal pins
RX3 ACC pin1 in + Internal pins
TX2 CAT out Connected in parallel to USB/serial CAT interface
RX2 CAT in use for CAT sniffing or TX request
D18 Encoder-B in pull-up internal (optional external*), Interrupt 5 (TX1)
D19 PTT foot in pull-up external, Interrupt 4 (RX1)
D20 SDA - ACC pin16 in/out I2C, Interrupt 3
D21 SCL - ACC pin15 out I2C, Interrupt 2
D22 PTT2 out
D23 FSK out keying from arduino
D24 Encoder-A in pull-up internal (optional external*)
D25 PTT3 out
D26 paddle Left in pull-up external
D27 WinKey out HIGH if CW keying running (disable DTR/RTS)
D28 paddle Right in pull-up external
D29 AFSK outHIGH if AFSK keying (switch TX audio path)
D30 ACC pin7
D31 PTT-PA out
D32 ACC pin8
D33 FSK detector in pull-up external
D34 CW1 out
D35 CW2 out
D36 MENU in pull-up external
D37 LCD-E out
D38 ACC pin11
D39 self reset out HIGH (enable with jumper JP5)
D40 Sequencer out
D41 PTT1 out
D42 BCD1 out TTL Band data
D43 BCD2 out TTL Band data
D44 BCD3 out TTL Band data
D45 BCD4 out TTL Band data
D46 Ethernet detect in pull-up internal
D47 ACC pin4
D48 Internal SMT pad Free
D49 Internal SMT pad Free
D50 MISO out
D51 MOSI out
D52 SCK out
D53 microSD CS out
A0 Internal SMT pad Free
A1 CW keyer Memory button in pull-up external
A2 LCD-RS out
A3 ACC pin12
A4 ACC pin13
A5 microSD plug in pull-up internal
A6 measure 3.3V in
A7 measure input voltage in coefficient 11
A8 ACC pin14
A9 ACC pin17
A10 - Free
A11 ACC pin19
A12 - Free
A13 - Free
A14 - Free
A15 - Free

  • If RC circuits installed