miracle2k / onkyo-eiscp-dotnet

Control Onkyo A/V receivers over the network; in C#, or on the command line. C# port of onkyo-eiscp for Python.

Onkyo eISCP Control, .NET version

This is a direct port of the PYthon Python version, and you should have a look at the documentation there to get started.

However, note that under "releases" you'll find a compiled binary of the command line tool that you can use to get started straight away:

onkyo system-power:on

is all you need.