t's important to check them out.
We have 3 answering machines and each is somewhat complicating.
When I say we have 3, I mean that two are packed away in the basement to be given away.
The best out of the 3 is a GE phone and it will ring 7 times before the answer comes on. It also has large easy to se numbers.
It's hard to know what your dear grandmother needs but for me I needed one that gave me time to get sat down to answer before the machine comes on.
Wal-Mart has a variety and I'm sure if you bought one that didn't work for her you could return or exchange it. In fact ask customer service before you buy and I bet they will accommodate you.
The others answered on the 3rd ring and I can't get to the phone in 3 rings.
Hope I was helpful.
DeeJay.
EDIT: As far as I know our phone company no longer supplies phones. AT&T supplies business phones but not for residents. Hopefully you phone company does.