The PDF attached in the link above contains the available API commands for the MXNet USP ecosystem. You can connect to the AC-MXNET-USP-CBOX's API server using PuTTY or other terminal clients, on TCP port 24, to execute the commands listed in the API documentation, or utilize the API commands listed in the PDF for device specific programming on third party control systems. 

API Version: V1.07

USP-CBOX Version requirement: V3.42.5 or higher