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Davac 4.2 OK1ZIA

Davac 4.2 is updated version of Davac 4.1. It is opto-isolated interface between PC and radio. Supports CW and SSB CQ, band recording. Radio modulation comes from microphone or soundcard.

Davac 4.2 PCB model
Davac 4.2 box model


  • Simple assembly
  • Most possible parts are SMD, except too expensive or unobtainable ones
  • Designed for SMD reflow
  • 3.5 jacks
  • 3D printed box
  • SMD LEDs + light guides on front panel
  • power supply from USB
  • pin header for band switching
  • nice logo on PCB and box :-)
  • radio-specific cables for different radios

Circuit diagram

Circuit diagram of Davac 4.2


Davac42-jlcpcb.zip Gerber files to order PCB at jlcpcb.com.


davac42-box.zip STL files for 3D printer.


  • Nozzle 0.4mm
  • No support, no brim
  • Layer height - first 0.3mm, others 0.2mm
  • PETG
  • Slow first layer for top side (8mm/s)

Print takes about 5-6 hours.

Light guides are made from transparent PETG filament.


Davac42-bom.csv Bill of material for tme.eu.

(not including cables)

Cable to radio

Program the FT232R

As default, the FT232R acts as serial port. But Tucnak uses Libftdi to access it in bitbang mode. Default VID:PID must be changed to distinguish Davac from other USB serial ports.


Use original ft232r_prog or modified ft_prog, contains statically linked x86_64 binary.


# ft232r_prog --new-vid 0xa600 --new-pid 0xe110 --manufacturer OK1ZIA --product 'Davac 4.2'
Rewriting eeprom with new contents.

Now replug the device

# lsusb
Bus 002 Device 007: ID a600:e110 Asix OK1ZIA Davac 4.x

(texts are not same, they origins from lsusb database)

In the case of mistake, use --old-vid and --old-pid. AFAIK this can be used also to fix fake FT232 bricked by Windows FTDI drivers.


MProg with loaded Davac4.ept

Under Windows, use MProg. Download File:Davac4.ept and open it in MProg. Note on Windows XP you need D2XX drivers; on newer versions they are installed automatically.

Unplug all other FTDI devices and press the Program All Existing Devices button.

Install USB drivers


You have nothing to do, It will work automatically. Only on specific distributions you may have to set permissions to USB device, which is normally done by udev script.


Zadig with Davac4

Under Windows 7 or newer, use Zadig. On XP use 2.2.

Click Options, List All Devices.

Choose WinUSB and press Install Driver.