IDTech Windows SDK Guide  1.2.35.0
API reference for SpectrumPro
Initialize SpectrumPro:

A Singleton instance has been established in the IDT_SpectrumPro class. Establish the callback, and then access the SpectrumPro through USB via the SharedController instance.

public SpectrumPro_Simple_Demo()
{
InitializeComponent();
IDT_SpectrumPro.setCallback(MessageCallBack);
}