Quite old thread, but I thought I share my findings on this one.
Unfortunately, the Cerevo FlexTally still can't be used via Ethernet with vMix. It still has to use the GPIO mode and an Arduino board.
Here is a step-by-step instruction about how to use the Cerevo FlexTally with vMix. (Tested with vMix 21.)
It's more or less pretty basic stuff so sorry, if I bore the advanced user.
I'm using an Ardunio Uno board with an USB connector, this has the advantage, that the Board will also be powered by the USB bus. Furthermore, I have soldered a cable according to the SUB-D pin connection of the FlexTally mainstation. I would suggest, that you get some pin headers which plug directly into the board. Makes it easier to solder.
I've also bought a SUB-D 15pin connector (I think a VGA-cable can fit as well, so you can simply cut an old one open and don't have to solder the SUB-D connector) and some cable, depending on how many contact closures you need.
I've bought this cheap Arduino plastic box where you can slide in the Ardunio.
I haven't done any fresh install lately, so I'm trying to remember all the right steps. I also think, that I've uploaded the sketch from a different computer, where the Arduino IDE was already installed. So please correct me, if I'm doing something wrong here.
Furthermore you need to install the Ardunio drivers and upload the Standard Firmata "Sketch" to the Arduino Board. Otherwise the Arduino does nothing, since it comes with no software installed. You can use the "Arduino Web Editor" which needs an internet connection but you don't have to install anything in order to upload the Standard Firmata, or - as I did - install the Arduino IDE on your computer. This will also install the drivers.
You need a USB2-A cable (the one with the big connector) and connect the Arduino to the PC - drivers should be found and installed by Windows automatically.
Follow the instructions on getting starting page for the Arduino UNO:
https://www.arduino.cc/en/Guide/ArduinoUnoBe sure to set the right COM-port and board you are using! In the menu "File->Examples" of the Arduino IDE there should be an entry "Standard Firmata". Select it one and push "Upload".
In the
vMix Help there is more information on the digital pins on the Arduino Board.
On the Cerevo Mainstation you have to turn off DIP switch #1 on the back to use GPIO mode. I have left all the other DIP switches in their default "ON" position.
Now, connect the Arduino to the GPIO SUB-D connector and start vMix. In the vMix Settings you can select which pins are to be used. I have turned off green preview, since I don't need it. For the start, just leave everything here as it is.
Open the settings of Input 1. Under "Tally Lights" select the COM port, to which the Arduino is connected to. And select to which Tally number this input should react. That's it!
Hope, somebody finds this useful.
Knut