My observations to Voice Mail and Call Blocking.
I've been a minor participant to the "in the last 25 hours" thread, reading all the great comments by CurtB and Bruce. I made some mention about voice mail and call blocking. I wanted to update my findings.
I have a newer Panasonic Phone hardware with an answering machine +250 call blocking button on the handset. The phone is set to answer at 4 rings. My COX phone system Voice Tools Settings has Call Waiting and Voice Mail (set at 5 rings) activated. My test was to call my home phone from a cell phone. Then I called my home phone from another cell and saw Me on "Call waiting" on the home phone. On my second cell, I DID NOT get a busy signal (probably because of the Call Waiting ON), but after 5-6 rings, an automated voice message comes on and tells me the phone is busy and leave a message...which I did.
I then went to my COX/Voice Tools and saw the Voice History and the Voice Mail message playback. So, if someone calls you and your phone is busy, all they would hear is a ringing tone and an eventual a pre-recorded voice requesting that the caller leave a message. You need to turn on Cox Voice mail under settings. I was able to verify other COX voice mail messages were left when our phone was busy by looking at the past history. I also have the a shortcut for the Call History on my cell.
I also saw phone numbers that were Blocked by me, either using the COX *60 feature (maybe about 30max) and my phone button Call Block (maybe max 250). In both cases when a call come in that is on either blocks, I see "Call Blocked" on the phone handsets window. The phone is set to ring only once. Not sure what message the Spammer gets, but a few keep trying over again.