Subnet Routing SNAP-PAC S2

There’s a little more to the story. While all you quoted is true, you still have the ability to write some code in the SNAP PAC. See this discussion: SNAP-PAC-EB1 Install Firmware via Ethernet Passthrough Connection

But I’m still interested in hearing about your “big picture”: the what you’re trying to connect and the why of what you’re asking to do here?