This will enable CAT control on your Mac running WSJT-X with the (tr)uSDX and possibly other USDX rigs as well. WSJT-X uses Hamlib to connecto to and manage CAT on different radios. The problem (thanks to Guido PE1NNZ for identifying), is that Hamlib resets the port when it connects. This causes the radio to reset and then it's not yet available when Hamlib tries to connect. We can work around that by blocking the ability for Hamlib to reset the port. The simplest way to do that is to have the port already in use when Hamlib starts up.
I was not able to achieve that using the Hamlib built into WSJT-X. However, by installing Hamlib separately,