@60hz You might be able to redirect a comport to your cheap usb device.
It is possible in windows using.......
NET USE COM1: //pc_name/printer_share_name /persistent:yes
The usb device has to be shared first......
https://superuser.com/questions/923426/how-to-map-a-virtual-com-port-to-a-physical-usb-port
The proviso about plain text would not bother you for a dmx dongle.
Further down the same thread you will see a link to https://ftdichip.com/drivers/vcp-drivers/
..... and on that page the virtual drivers for windows.
They mention "D2XX Direct drivers" are included...... and I have a very vague recollection that it is they that do the FUDI stuff.
They only mention windows....... and then further down the page are drivers signed by Apple, and quite a few others.
The virtual drivers should make the device appear as a comport.
You can see on Amazon that a few people needed these virtual drivers to make the device you have work with FreeStyler....... where they then select Enntec DmxPro as the output.
In Freestyler selecting the Enntec is essentially choosing to communicate through a comport rather than through a driver interface.
When you select the DMX Pro in Freestyler it asks which comport (years since I have used it... but pretty sure)
David.
P.S. I forgot to mention yesterday that you could send your data directly from the RPI using Python (maybe Python is already involved) and call pdsend....... probably pdsend.linux which is in the Pd folders somewhere.
That would send directly over Ethernet to a [netreceive] on your computer.
Approximate usage..... https://guitarextended.wordpress.com/2012/11/03/make-python-and-pure-data-communicate-on-the-raspberry-pi/
I assume (I do that a lot) that
pdsend (your computer IP address):(port) would send correctly...... something like pdsend 192.168.1.33:3000 would send to [netreceive 3000] on your computer.
You mentioned an Ethernet shield...... does your RPI not have an Ethernet port built in ?...... I thought they all have one.