Hi, Stephen. I’m glad you liked the article.
Regarding your question about legacy devices: regular legacy devices won’t slow down your network. That means your printer is fine.
Your Vonage phone adapter might slow down your network, depending on how you use it. I used to have Vonage and the adapter they gave me (model VDV21-VD) has two RJ-45 ethernet jacks on the back. The uplink jack was supposed to plug directly into my cable modem and the other jack was supposed to plug into my router.
If that’s what you do (and you have a 10/100 legacy ethernet Vonage phone adapter), then your Internet connection will be limited to 100 megabits. You can get around that limitation by plugging the uplink jack directly into your router the same way you plug in your printer. (That’s what I did and it worked for years without any problems.)
On the other hand, unless you have super-fast FiOS, it doesn’t matter where you plug in your Vonage phone adapter.
About the router indicator light: I can’t be sure without researching 2010 Mac Pros, but your Mac probably supports a protocol called “Wake On LAN” which allows another computer on your network to send it a special ethernet[*] packet which will turn on the Mac. It’s nifty to watch, but almost useless on a home network. (Large offices and server farms use wake-on-LAN all the time.)
In order for wake-on-LAN to work, your Mac needs to send a tiny bit of electricity to the router so the router knows how to find the Mac when the wake-on-LAN packets are sent. That’s why you see the light. Although wake-on-LAN could use gigabit, the authors of the Mac firmware driver probably made it use 10/100 legacy ethernet so that it would support legacy routers. Once your Mac turns on and sees that the router supports gigabit, it also switches to gigabit, so you have nothing to worry about.
If the light annoys you, you may be able to disable wake-on-LAN in your Mac’s BIOS. I’m mostly a PC guy and I never learned how to change Mac BIOS settings, but if you search Google for something like “apple bios wake lan”, you’ll probably find instructions. (On the flipside, if you check your PC’s bios, you may be able to turn on wake-on-LAN.)
I hope that answers your questions.
Thanks for reading Tips4PC!
[*] Unlike almost everything else on your network, wake-on-LAN doesn’t use the TCP/IP protocol which powers the Internet. It’s a ethernet-specific protocol–and that means it confuses a lot people (including some system administrators I’ve met).