Phone:
Plugged in the base phone, got online and it was activated instantly. Doesn't appear to work for old fashioned rotary dial phones.
There are more things you can activate:
Call Forwarding (busy, exclusive, or no answer)
Call Blocking (block up to 20 numbers), and Anonymous call blocking (those with hidden caller ID). Not sure if that includes "caller unknown"
Call Screening (accept up to 20 numbers)
Voicemail
Don't know if these things will play nice with the device I already have that blocks calls, or with the answering machine on the base. I'm taking a break before experimenting further. Need to experience a simple success for at least a few hours in order to build up some confidence before proceeding. LOL!
Still haven't completely given up on activating the old house wiring. Don't know why really.
[SUP]*[/SUP] I guess just to see if it can be done.:shrug: Trying to translate this rather old answer, from an AT&T forum, into English.
POTS - Plain Old Telephone Service
[SUP]*[/SUP]A reason---so there can be one nice looking phone downstairs, and a wall phone upstairs.
Update 7:30 pm:
My blocking device works just fine on the new phone, and has more options than the phone service, like wild card numbers (blocks 80*, 88*, etc). So the only AT&T option I might be interested in is Call Forwarding (exclusive). You might be able to use this to receive calls from businesses and avoid giving them your cellphone number to sell. I think that happened with Tractor Supply this summer.
All the house phones are still working, even the rotary dial one, but I expect that will change.

After reading over that AT&T forum answer, I think I understand it, except exactly how to wire the double jack wall plate. I may have done that already on the upstairs hall phone, but skipping the wall plate.