But most of the time you can use a HUB. Switched hubs are cheap here. Example:
https://www.amazon.com/TP-Link-Ethernet-Splitter-Unmanaged-TL-SF1005D/dp/B000FNFSPY should be ashamed to call it a splitter. But it's cheap.
Using Vonage successfully via ethernet jack. Using desktop successfully via same jack. BUT.... I cannot have them both plugged in at the same time so I either can have a phone for when the dozens of doctors call me (I am homebound and ill) or I can have my computer running with internet. So many apartments here all using the same wifi and jamming it up so my wifi is seldom used.....I really need the ethernet connection!
Purchased a splitter (not phone, but the real ethernet style) which works so far, only as a silly cord extender. Can only plug one or other into it. When both plugged in, my computer ethernet connection dies.
I am so techdumb that I do not know if Vonage uses a completely different type of communication thru that jack and thus messes with the computer attempting to do the same simultaneously.
I have read too many horror stories about Vonage not helping its customers so am coming here first.
Thanks for reading, thanks in advance for any possible assistance.