After bringing together EhoCW, VoiceMeeter Banana and Mumble, I built an interface for my paddles using the following:
1 - Sewell USB-Serial Adapter (I had this on hand, a similar one is available on Amazon)
1 - 3.5mm Stereo Female Terminal Block panel mount connector
1 - DE-9 (DB-9) RS232 Female Soccket Connector to Terminal Block
Using the above it was trivial to create a patch cable for my various paddles. The connectors came in 2 packs, so I'm going to make one for my straight keys as well. Dit -> tip (pin 6), Dah -> Ring (pin 8) and Common -> Sleeve (pin 4). For Straight keys, pin 4 and pin 6.
Working very well, loopback works well. Looks like I'm all set!
73 de Mark KD8EDC