OK, now I am VERY confused.
The modem/router is an Arris Interactive 1706A
Specs from their support page:
As you can see in the blue boxes, it has one gigabit port and 802.11n WiFi.
[But, a troubling aside, it also lists having MoCA technology and a guest wireless feature, neither I've seen in actual use]
I looked at the 4 LAN ports and there is nothing to distinguish the 1 Giga port.
From the instruction manual:
As an indicator light is all there is to identify the Giga port, it would seem that the modem adapts to provide Giga access to whichever port is pulling Gig speeds?
As of right now, I only have amber lights appearing for the connected LAN cables.
FYI, the cable connected to my desktop is a rated CAT6 (https://www.amazon.com/gp/product/B...ag=hawk-future-20&ascsubtag=UUwpUvbUpU3604542
Still awaiting brown truck delivery of my USB adapter.