nomorobo worked perfectly.  One ringy dingy, and disconnected.

Called our DNC registered landline on 06/18/2014 @ 12:19 PM from Russia according to my online records. Another commenter also mentioned Russia. (723) is not a valid US area code.
Caller ID shows Name Unavailable. No message was left.
I have gotten calls from Peru and Vietnam also. Like Russia. It's probably also a spoofed number.

Any machine has to pick up the call in order for it to search for the number on your blacklist. Most machines allow one ring while doing the search. If there is a match, your machine hangs up and that is what the caller or robo caller knows. It knows your number is valid because the call was answered and hung up on just as if you had done it yourself. That doesn't mean the caller will stop calling. The machine will continue to hang up on that number. A savvy telemarketer may try a new number you haven't yet blocked.
My phone company allows me 32 free blocks. If a blocked number calls, it's blocked at the phone company before my phone rings so I'm completely unaware if I continue to get calls from that number.

Thank you for the information. I checked my current phone and don't think I am able to block calls from it. I will look into it. Would you know if the callers will reach anything stating their calls are blocked? Just curious.

I just got a call which I will add or have already added to my block list.  I will now get no ring but I will be able to get list of blocked calls on my phone.
I have the Panasonic cordless telephone  Model kx-tg6842b (2 handsets)
You can block 250 numbers plus kill the one ring that existed on earlier models that only allowed 30 blocked numbers.  The one handset model sells for $70 at Amazon.

I also got recently the Pro Call Blocker version 2.2 which allows blocking 10 area codes and 1500 phone numbers plus Private, Unknown, and Out of Area calls.

Male with heavy accent said it wasn't a sales call and asked for me by name when my son answered. When I called the number back it said your call cannot be completed,  check the number and call back.

These people need to be put in jail for this scam. Trying to ask all kind of personal information that they say is need before they can talk to you. Hello were is the fcc in all this the vest is I  told the guy I was Elmer  frezze from down under and this guy says nice to neetyou Elmer dum a**

Telemarketer.  Heavy accent.  Male.  Wanted to talk about solar panels.  I hung up.

Looks like another low life scum sucking  bottom feeder has surfaced. Will ignore them as I do with the rest.

I am so tired of these people. I do not answer, block and they just keep calling from other numbers. It is a joke that something is not done.

They called my house phone.  No one there, dead silence.

Just got a call from this number . . . no message  . . .  no nothing.   What BS the "do not call list" is  :-(

foreigner with heavy accent said something that i could not understand, told him to stop calling this number

It is a Russian number - not from USA.

Spoofed phone calls made on reverse phone number system, So annoying.

I keep getting these calls and don't answer them. Seems like the phone companies should be able to find these people and do something about them.

Everytime I go on it. Scumbags call me all hours like real shameful svummiieesssss

723 area code (non existent) any # with this prefix is spoofed.

called back got a recording said number not valid