You'll need to configure the Acuity: on the Comms menu under RossTalk port (Xps), you will need to provide the IP address of teh MDK-111-K card. You also can configure the port number here, the default is 7788 (make sure both devices match).
Then you can create custom controls (macros) to trigger the RossTalk functions. There are two options: ASCII (with automatic CRLF) and HEX (without any extra CRLF). The ASCII option is what you want here.
The possible RossTalk commands are described in document 4802DR-403-10. In a nutshell, for the MDK-111-K, you will use these strings:
KEYCUT 1:1 --> to toggle the first keyer
KEYCUT 1:2 ---> to toggle the second keyer
Similarly for the other keyers. To fade instead of cutting, use KEYAUTO rather than KEYCUT.
Our tech support team is available to help you set this up. They can be reached by email or phone, please see
https://www.rossvideo.com/support/tech-support/#openGear