Call Blocker 3.1, Most Effective Spoof Call Blocker, Blocks 100% ROBOCALLS, Scammers, Election Calls, Telemarketers, Solicitors.

Note the word "Screener" in the title. Others have described in detail the operation of the device, so I'll try to summarize. Although advertised as a call BLOCKER, unlike every other call blocker, it does this by actively SCREENING your calls, before they actually get through to your phone line. It maintains two lists - an ACCEPT list and a REJECT list - and it has a built-in voice recorder that records caller messages (up to 20 seconds, and limited to 2 messages). The total of stored numbers retained on both lists, combined, is limited to 1,500. There are no preprogrammed numbers installed in the device. This seems modest compared to other units, until you know how it operates:If the caller is on the ACCEPT list, the call will ring through normally, either for you to answer, or to go to your voicemail or answering machine. The ACCEPT list caller will never know you have a blocker. If the caller is on the REJECT list, the phone won't ring, and the caller won't get through (although they will show up on Caller ID on the Sentry).When a call arrives, not on EITHER list (that's an important distinction), your phone will either ring one time or none - depending if you have the device set to 1 ring or none (some phones won't display Caller ID if there are no rings, so you may need to put up with one ring to see Caller ID on your phone). If that's not important to you, or your caller ID shows up with this setting, the 0 ring setting keeps your phone silent (remember, this is a call from someone or some number you don't know or are not expecting to call). What the CALLER will hear is a message that basically tells them if they are a telemarketer to buzz off and take you off their calling list, OR, if they have a legitimate reason for calling, to press 0 and leave a message after the tone. If they don't press 0, the call ends and the caller is cut off, but they don't end up on either the ACCEPT or REJECT list. If they do press 0, the Sentry unit itself will then ring 9 times (not your phones), after which a tone will sound and the caller can leave a message on the Sentry, which will display a flashing red light that a message is waiting - and they will be added to the ACCEPT list by default (they'll be added as soon as they press 0, but they won't know that). You can then, later, decide if you want to keep the caller on the ACCEPT list, or transfer them to the REJECT list after reviewing the Caller ID and the message. Or you can answer the phone during the 9 rings if it's a call you want to take.That's it, operationally, in a nutshell. There are distinct advantages to this approach, and some disadvantages, and the devil is in the details, below.The advantages are:- Robocalls will not be able to press 0, so will be automatically cut off. No more robocalls, hence no need for a list of thousands of pre-programmed robocall numbers (which may change daily anyway, leaving the pre-programmed list useless).- Telemarketers, historically, want an easy call, so pressing 0 and hanging on through nine rings will not be in the business model of 99.9% of them. And for the 0.1% who DO persist and leave a message, you can simply add their number to the "REJECT" list. And when they change their number - and they will - they'll have to go through the whole "press 0" exercise again.- This device also has the ability to add up to 10 area codes as REJECT list number, so whole area codes (as in known overseas spammers using a specific area code) can be blocked (although not added as universal ACCEPT area codes).- You can customize the message played on the recorder to whatever you want to say to the unknown caller - for example, neglecting to tell them to press 0, so that NO call will get through, unless you have added it to the ACCEPT list. A bit Draconian, but assuring complete privacy unless you have specifically given permission to a specific number to call you. No other blocker will do this.- It can be set to automatically reject all calls with no Caller ID, such as the mysterious Unavailable, or Out of Area. Realize, if you do this, you may block legitimate callers (some healthcare providers for example, who blank their numbers).- You can manually turn off the "Sentry" part of the device - meaning it will operate as a normal call blocker, allowing calls from everyone not on the REJECT list, unless and until you block them, up to 1,500 numbers and 10 area codes.And some disadvantages, which may or may not be important to you, or even obvious:- No more robocalls. Yes, that was listed as an advantage. It also means no more automatic reminders for clinical appointments, or car servicing, or pharmacy pickups, unless you add those numbers to the ACCEPT list. And no more incoming faxes on your phone line, unless you add those numbers too, or unless you turn off Sentry temporarily (which, fortunately, you can do).- Legitimate callers, that you have not added to the ACCEPT list, could easily be confused and just hang up. The default message (that probably most of us will use) says press 0 and leave a message after the tone. It doesn't say anything about 9 rings (which are warbly and sort of feeble, as is the tone following). And you can only leave 20 seconds of message, which could cut them off mid-sentence.And there are hardware pluses and minuses:- Not related to its Sentry function, but it takes 3 AAA batteries to see the LED screen (which is not backlit), that must be replaced periodically (6 months or so, but it does notify you on the unit to replace them). And all calls will come through when these are out - and you'll lose your data unless you put fresh batteries in within a few minutes. It also means it doesn't need an outlet or other external power source, if location is problematic - a plus.- The LED screen is obviously not as readable as a backlit screen, but you can adjust the contrast slightly.-The 9-ring function, after an unknown caller presses 0, only occurs on the Sentry unit - not on your telephone(s). If you're in another part of the house, you may not even hear it to know that someone is calling, although, presumably, they'll leave a message, if they wait for 9 rings and a tone. Remember - this will only be callers not on either ACCEPT or REJECT, but it could be, for example, from your bank. Or your long-lost Uncle leaving you his billions in inheritance, but only if you answer the phone. Or your Sweetie accepting your marriage proposal. Or rejecting it. Best to add all the ACCEPT numbers you can think of, in advance, and this fortunately is relatively easy to do, including names (15 or so character-limited, all caps).- And the menu is somewhat quirky - entries are arranged sorted numerically (by phone number) rather than alphabetically for example, and Caller ID time is only displayed in the 24h format.- It only stores two messages. If three callers dial in (that you have not added to your ACCEPT list) with urgent reminders to take three different cardiac medications, you'll miss one - it stores first in, first out.- You can't block calls remotely from other wireless phones on your phone line, which many other blockers allow.- And, it's large. Around 6" x 5." That's two or three times the size of most other blockers, if counter space is an issue. This does allow space for a keypad though, which is a definite plus adding numbers and names.With all of that, warts and all, it is one of the more effective and capable devices for eliminating irritating unsolicited calls in your life - it will always be up to date, and it will automatically screen the majority of unwanted calls with no other action on your part than turning it on. Recommended.

Sentry Active Call Screener V3.1Pros: It blocks ALL calls from any robocaller, telemarketer, survey, or political campaign the way that I have it set up with a “whitelist”. That's enough for me to give it 5 stars!Cons: It won't be perfect for everyone. It might not COMPLETELY block all unwanted calls for you unless you set it up something like I did. Also, the volume for the outgoing message that you can record on the Sentry is too low, and is not adjustable- but it's adequate for my needs. I understand that the sound volume and quality on the built-in answering machine is also poor, but I don't use that feature. I wish that it had a feature where you could whitelist an entire exchange since some businesses are so large they don't share an exchange (e.g. whitelist 212-555-xxxx). My method for connecting my Sentry might be technically challenging for some users.I still need to have a wired landline, but I was being swamped by nuisance robocalls so I bought this call screener. I wanted a call screener that would not allow my phones to ring unless I wanted to hear from the caller, and this screener fills the bill perfectly.Having a “blacklist” of blocked callers wouldn't work for me because of the large number of robocallers that just spoof their caller ID and use a different one for each call. Almost all of the unwanted calls that I was getting would get around any blacklist, so I need a screener that uses a whitelist. I have relatively few numbers that I need to allow to call this particular phone number so I was easily able to set up a whitelist of about 20 callers for the screener to allow through, and all other callers are blocked. If you have a very large number of callers that need to reach you it could be a hassle to enter all of those numbers into the screener for a whitelist, but if you can enter them all, it works.When I first plugged one of my phones into the Sentry it worked perfectly, but only for the phone that I had plugged into it. The device only works to block calls completely for phones that are wired in series- in other words, directly connected “downstream” from the Sentry. All other wired phones in the building, and the wireless phones that didn't have their base station plugged into the Sentry would ring one time when a blocked call came in before the Sentry would block it.I didn't want ANY phone to ring AT ALL for a sales call, so I wired the Sentry into my building's telephone distribution module (  Linear DMT-16 Linear/ChannelPlus Telephone Distribution Module with Surge Protection  ). The wire that comes from the telephone company's network interface box goes into the Sentry. The Sentry then has a wire that goes to the telephone distribution module which then sends the calls downstream to each individual phone. ALL unwanted calls get blocked and NO phones ring when a call not on the whitelist comes in. The blocking of unwanted calls is completely transparent to anyone in the building, and the Sentry screener is completely transparent to callers on the whitelist. (Except that the first ring the caller hears on their end does not ring-through to the phones. The Sentry doesn't start ringing the phones in the building for whitelist callers until the second ring.) The Sentry is, of course, also completely transparent for outgoing calls.By the way, the message that I recorded in the Sentry for blocked callers to hear is AT&T/Bell Telephone's recording of “This number has been disconnected or is no longer in service”.***CONCLUSION***: If you can connect the Sentry Active Call Screener V3.1 in series with all of your phones (for example, if you only have one wired phone or cordless phones with one base station that you can plug into the Sentry) AND you are comfortable with typing in a whitelist for all of the callers that you might want to hear from, this screener can block ALL calls from unwanted numbers and not affect wanted calls.(Now it gets more technical for anyone who wants to know details on how I wired the Sentry between the telco's network interface and the building's telephone distribution module.)The network interface is outside of the building and the telephone distribution module is in the attic. That would be too hot/cold for the Sentry so I had to run wires into the building. I have Cat5 wire running from the network interface that I disconnected from the distribution module and terminated in a RJ11 jack. I then ran a standard off-the-shelf 33' telephone cord from that jack into the building to the “Line” jack on the Sentry. I then terminated a Cat5 wire with a RJ11 connector, plugged it into the “Tel” jack on the Sentry, and then ran the wire back into the attic where it connects to the distribution module with a 110 punch down connection. The extra 66' of wiring did not seem to degrade call quality and having the Sentry between the distribution module and the network interface does not seem to affect the security system's ability to call the monitoring center.