The version (V1) of this multi-port ‘universal’ radio controller is a simple device that sits between your computer and transceiver and provides the following functions:
1) USB-C sound card to convert the receive/transmit audio from the transceiver to USB
2) Full PTT control to allow automatic receive & transmit using either serial port settings (DTR & CTS) or the CM108 standard supported by popular software (including DireWolf)
3) Dedicated connections tor connecting HT (Handie Talkies) that will also provide serial port programming of the HT with CHIRP or the manufacturers software. Makes such as Baofeng and Quansheng will work with this.
The connection to the radio is either by a TRRS 3.5mm Jack wired:
- Tip TX Audio (plug into the Mic socket)
- Ring 1 RX Audio (from your speaker socket)
- Ring 2 PTT (active low – connect to your PPT line)
- Sleeve Ground
(This connection is wired the same way as the Digirig standard so you can use those cables if you have them.)
Or use 3 discrete 3.5mm jack plugs for:
- Receive Audio
- Transmit Audio
- PTT
Or use a OHIS.ORG wired cable.
- OHIS is an emerging standard for connecting equipment and headsets to transceivers
- This unit will sit between the radio and the user device as a pass-through.
- It allows the sound card features of the unit to overlay the TX/RX audio and provide PTT control so can be used for a variety of purposes such as announcements & recording as well as digital modes.
Or use a pair of cables to your favorite Handy Talkie
- There are two sockets on the modem to connect to the 2.5mm and 3.5mm connection on your HT
- The sockets are both 3.5mm at the modem end
- Wire the plugs pin-to-pin (tip to tip, ring to ring, Sleeve to sleeve) and you are good to go.
- Full TX/RX audio and PTT is available as well as the ability to program the HT using CHIRP or your favorite software.
You can also use VOX to key the transmitter if you prefer.
The inbuilt monitor allows you to listed to the received audio at the press of a button and is very useful where the radio audio jack switches off the radio speaker.
The unit is shipped with the firmware loaded and tested on APRS. It is fully powered by the USB connector so ideal for mobile/portable operation.
The CPU used in this unit runs the open-source firmware used on the AIOC and full software support can be found here: https://github.com/skuep/AIOC .
How To Use
The serial interface of the unit enumerates as a regular COM (Windows) or ttyACM port (Linux) and can be used as such for PTT (Asserted on DTR=1 and RTS=0).
The soundcard interface of the unit gives access to the audio data channels. It has one mono microphone channel and one mono speaker channel and currently supports the following bitrates:
- 48000 Hz (preferred)
- 32000 Hz
- 24000 Hz
- 22050 Hz (specifically for APRSdroid, has approx. 90 ppm of frequency error)
- 16000 Hz
- 12000 Hz
- 11025 Hz (has approx. 90 ppm of frequency error)
- 8000 Hz
A CM108 style PTT interface is available for public testing. This interface works in parallel to the COM-port PTT.
If you are using DireWolf, add this line in the PTT section (change to match your com port assignment):
PTT COM4 -RTS DTR
Tip: I use these pre-wired TRRS cables cut in half (so you have 2 fully wired plugs) to connect transceivers with a speaker-mic plug: https://www.ebay.co.uk/itm/224931219020
As with all technical products there are some bugs and undocumented features. I am maintaining a log of any issues on the CPU page: https://g1lro.uk/?p=122