SoundCheck can be externally controlled using TCP/IP and ActiveX (Windows only). The SoundCheck manual describes these programming structures. You can also find LabView, C#, C++, Visual Basic examples using TCP/IP in the "External Control Examples" folder in the SoundCheck installation folder, with a subfolder for ActiveX examples in C#, C++, and Visual Basic.
As of SoundCheck 15, both controls are available but ActiveX support has been deprecated and will be completely replaced by TCP/IP. Any ActiveX controls should be converted to TCP/IP.