Mike
OK... You need to connect from your USB To RS232 converter lead
GRD (Black)....... rj12 pin 1
TXD (Orange)..... rj12 Pin 2
RXD (Yellow)..... rj 12 Pin3
The wire colour is from the diagram link suplyed for the RS232 to USB the colours may be difrent from an alternative RS232 supplier please check with the supplier.
The Diagram can be found on page 7 from the link below
http://www.ftdichip.com/Support/Documents/DataSheets/Cables/DS_USB_RS232_CABLES.pdfThe Pin order for the rj12 for LX FLARM are shown on the Redbox instructions page 10 See link below
http://lxnavigation.com/downloads/manuals/Flarm/Flarm-red-Box-SD-IGC-26-6-2013.pdfLooking at the instructions on the FLARM Mini box it indicates the pins out are the same so it should work, they are on page 3 and states .....
• Pin 6 power input (8-16V), 4 and 1 GND (near to RF connector), 2 data in, 3 data out, 5 power for
external display
You do not need the power on pin 6. Do not bother with pin 4 & 5 ether.
Instructions here ....
http://www.cssleszno.eu/files/LXFlarmMiniBox.pdfHopefully you have now all the info needed. Just make sure you put the rj12 the correct way around when you crimp the plug onto your RS232 usb. (I did my first one the wrong way around) The wires are a little tricky to push into the rj12 plug too
If you are still un-sure we could make one up for you.