AIOC

This is the Ham Radio All-in-one-Cable.

What does it do?

The AIOC is a small adapter with a USB-C connector that enumerates itself as a sound-card (e.g. for APRS purposes) and a virtual tty ("COM Port") for programming and asserting the PTT (Push-To-Talk).

Features

• Digital mode interface (similar to digirig)
• Programming Cable Function via virtual Serial Port
• Compact form-factor (DIY molded enclosure TBD)
• Based on easy-to-handle STM32F302 using internal ADC/DAC (you can program these without any additional tools using DFU
• Tested with Wouxun UV-9D Mate and Baofeng UV-5R
• Should theoretically work with APRSdroid on Android see below

Future Work

• Enclosure (DIY using 3D-Printed mold and Resin)
• Maybe integrate a TNC Modem with KISS interface? (I am not sure if that is worth the effort)

How To Build

• You need to use Monacor PG-204P and PG-203P or compatible TRS connectors (2 solder lugs and a big tab for the sleeve connection)
• Cut the 2.5mm and 3.5mm TRS sleeve tab where the hole is located
• Put both TRS connectors into the solder guide (or a cheap HT that you don't mind potentially damaging). Make sure, that they are seated all the way in
• Solder sleeve tab on the back side for both TRS connectors first
• Turn around PCB and solder remaining solder lugs

How To Program

• Short outermost pins on the programming header. This will set the device into bootloader mode in the next step.
• Connect USB-C cable to the AIOC PCB
• Use a tool like dfu-util to program the Release Binary like this (see more information at https://yeswolf.github.io/dfu/):

  dfu-util -a 0 -s 0x08000000 -D aioc-fw.bin
  

• Unplug and replug the device, it should now enumerate as the AIOC device

How To use with Direwolf for APRS

• Follow the regular setup guide with direwolf to determine the correct audio device to use
• Configure the device as follows

  [...]
  ADEVICE  plughw:<x>,0
  ARATE 48000
  [...]
  PTT /dev/ttyACM0 RTS -DTR
  [...]
  

How To use with CHIRP for programming

• Start CHIRP
• Select Radio->Download from Radio
• Select the new COM/ttyACM port and start

Notes on APRSdroid

Although theoretically not an issue, currently APRSdroid is not supported due to the following two issues:

• According to https://github.com/ge0rg/aprsdroid/issues/156 the sample-rate is fixed to 22050 Hz. Currently, only 48000 Hz is supported by the AIOC (and 24000 Hz or 12000 Hz would be possible to implement). However the required hard-coded 22050 Hz would require a different timebase or resampling and is thus not possible unfortunately
• Currently APRSdroid does not support any PTT control via a serial interface. See https://github.com/ge0rg/aprsdroid/issues/324 However my previous experience is, that the Android kernel brings support for ttyACM devices (which is perfect) so implementing this feature should be no problem.