Hi all,
I can not report success, but I will detail what I have done so far. After reading, perhaps you can tell me what I am doing wrong.
I have modified an FTDI FT232R based USB serial interface dongle by removing the RS232 level shifter, connecting the VCCIO line to 3.3V (instead of 5V) and connecting to the FTDI chip's Tx and Rx lines directly. These are wired to a 3-pin (stereo) 3.5mm socket. Tip is data in to the PC, ring is data out from PC, sleeve is ground.
I also made an adapter for the 4-pin 3.5mm plug on the VX2r. Tip is N/C, 1st ring (data/clone) is connected to Tx *and* Rx above, 2nd ring (mic+ptt) is N/C, sleeve is ground.
The dongle still works, and when I plug it in it is assigned to /dev/ttyUSB0
When I plug the adaptor in (but not the radio) then I have basically made a loopback device, and I can use gtkterm to view echoes of every character I type.
I have modified chirp and copied the VX7 module to make a VX2r module. I can run chirp (in Linux) and select VX2r and the /dev/ttyUSB0 port.
When I plug the radio in I press FW whilst turning it on. The display says 'CLONE'. Next, I press BAND, because I want to Tx from the radio to the PC. The radio display says 'TX'.
Nothing happens in chirp (I guess I am supposed to see an animated progress bar) and the radio eventually times out and shows 'ERROR' on its display.
Please point out my obvious mistakes and I will try again. :)
73,
Andrew ZL3AME