Call Blocking revisited

[jimandy]

I am back to grousing about calls from politicians wanting my vote, charities, wanting my money, and surveyors wasting my time. And, I’m thinking about the kind of call blocker I would use. My specs are simple.
1. Would use two answer machines, one for intercepted trash calls, the other, my regular in-the-phone unit to take acceptable calls when I’m not here.
2. Would only ring my phones for any call with a CID phone number matching a built in phone list, other calls routed to the intercepting answering machine.
3. Could load it with acceptable caller numbers from my phone lists that live on my laptop and iPhone phone via USB , or whatever.

Those are all the features I want. No more, no less. Any suggestions?

[jimandy]

The calls have gotten worse, mostly political messages and surveys. I am on the do-not-call list but it doesn’t seem to cover these types of calls.

In my earlier posting I described what I want in a call blocker and I think I found a possible solution. The call blocker made (or distributed) by JF Tech. Development Company (http://www.jfteck.com/) seems like it would do the trick once programmed with my “friends & family” phone numbers (F&F) from my laptop and cell phone contact lists.

If I hook it up with an answering machine on the inbound side then I would have a message telling the caller to leave a phone number and reason for the call and maybe I will call them back. Otherwise the calls ring through.

The only problem is that programming the numbers will be tedious as it has no numeric keyboard. My options at this point then seem to be…
1. Buy one and spend hours manually entering the numbers.
2. Open it up and modify it with a kluge to the existing switches from a Stamp (or whatever) and write code to interface with my PC to dump the numbers in.
3. Start from scratch and build a custom unit with a USB port for importing the F&F phone list

Again, I appeal to anyone who has reached their tolerance level on the irritating spam calls and is interested in such a project, to offer suggestions or collaborate with me on implementing option 2 or 3 above.

Note: The caveat with this device is that the caller ID data does not display on the house phones since they don’t ring until a call has been checked by the blocker and passed through to ring if caller is on the list. I’m working on an idea to use a CID unit that “voices” the CID info, records it and delays it for a few seconds then plays it back (if the call is passed through) to a speaker near our phone set. Better ideas would be appreciated.

[ltx71cm]

I'll do some planning later today and let you know where I get but I've wanted a similar product for a long time. I just never got around to making it.

My plan was to use a PIC to manage a block list and parse incoming caller id data. If the caller passes test one, I'd allow the house phones to connect and make use of the forthcoming rings. In between actual rings 2 and 3 I'd inject the caller id data into the line for the house phones so they all work as normal.

They make phones that speak the incoming name so that is something I wouldn't handle. Having the project installed has only one noticeable side effect. Allowed callers get 5 rings instead of 4 before the answering machine picks up. No big deal.

The are a few problems that need to be solved though. I can't leave the house phones disconnected all the time or no calls could go out. I can't leave them connected because they would ring for possibly blocked callers. I could try to detect a ringing voltage and rapidly and temporarily disconnect all phones whilst leaving the call blocker connected (for the duration of the first ring). I could leave the phones disconnected and try to sense one going off-hook. Another problem being that to work properly the call blocker needs to be in position one with the ability to control the other phones. In my home this is easy, I know where my phone line enters and have immediate control of it, others might not be so lucky. Of course now that task is easier since we use a VOIP modem and the modem is position one. It would be trivial to intercept bad callers in my case. VOIP itself brings up another issue, is it really worth the hassle these days? My phone company offers call screening and call block. I believe the service is free to use but I've never tested that theory. I mostly use a cell phone these days and all but ignore the house phone completely.

All that being said I have the CID decoding and encoding handled as well as ring detection and data parsing. I plan to use at least a 1Mb EEPROM for storing the block list so there is no chance of not having enough storage. The problems I've yet to address are those mentioned previously.

Comments are welcome.


jimandy I sure hope you never sent JF Tech money or you mistyped their URL. The site appears to be gone. I thought I visited the link when you first posted it and it worked though. Odd.

[haklesup]

what features does the voice mail service from your phone provider offer? What services are available if you switch to say a cable or VOIP provider for phone service? You can usually preserve your number when you switch.

I ask because my cable based phone is very feature rich but I checked and selective ring is not there. I think selective ring coupled with selective blocking would help.

[jimandy]

ltx71cm, You have done an excellent job analyzing the logic of the system. A major hurdle, as you pointed out, is having house phones initiate a connection to the outside line. This would suggest the system emulates exactly what the telco does to detect off-hook condition, a secondary current loop through the house phones.

BTW I had no trouble accessing the JF Teck website via a click on the link in my previous post. Try Googling “JF Teck” or “Caller ID with Ring Control”.

They make phones that speak the incoming name so that is something I wouldn't handle.

I'm working on the idea of recording the Voiced CID and replaying (delayed) over a PA system in the house. (see my topic "Record-Delay-Play sound-bytes".

The annoyance this type of system is trying to overcome is the new-found ability of telemarketers to "spoof" CID info with an innocuous looking name and number. Apparently,in this election year, the politicians are paying big bucks to the spoofers to get their messages through all the traditional call blocking systems

[ltx71cm]

haklesup I currently have VOIP service through my cable provider, along with internet services. Some of the pertinent features they offer are:

• -Anonymous Call Rejection
  -Call Screening
  -Selective Call Acceptance

I'm leaning toward detecting an off-hook condition over the other options. It seems the most reliable and easy to implement.

It might be a good idea if this becomes a working project to have an emergency phone connected before the add-ons with the ringer off.

The annoyance this type of system is trying to overcome is the new-found ability of telemarketers to "spoof" CID info with an innocuous looking name and number. Apparently,in this election year, the politicians are paying big bucks to the spoofers to get their messages through all the traditional call blocking systems

To fix that issue the system could use a white list model, only names and numbers listed get through, everyone else gets played a nice "no thanks" message. This does bring about a problem if loved ones call from a friends phone but I think I have a solution to that too. What if people we trust have a "code" they can enter that will ring the phones by bypassing the blocker. If someone calls they can dial "1234" during the "no thanks" message which allows them to call back and get through. A hassle yes but it's an option. To one up this feature a ringing circuit can be added to ring the internal phones after code entry which negates the need to call back.

[MrAl]

Hello,


I just wanted to mention that this is something i have thought about in the past also and would like to have something like this too, with the ability to completely ignore some calls yet let others through based on various things about the incoming number. I get the strangest calls sometimes from very strange numbers too like 1-888-888-8888 for example.

I guess my requirements are fairly simple, direct calls that meet a certain set of criteria to the normal answering system and just ignore the others. The setting of the criteria gets a little involved though. I dont want to ignore calls just because the number isnt recognized as that might miss some good calls that are from new callers. This would mean new numbers would have to be let through. The problem with this though is that some companies keep using a different number each time they call maybe so they can get by systems that store the numbers and ignore by number. This means some more thought would have to go into this kind of thing. It would certainly help ALOT for the repeat pain in the azz's thought, that's for sure!

Did anyone here design any code yet for obtaining the incoming call information from the line (perhaps with a circuit) or didnt get that far yet?

[ltx71cm]

I've gotten as far as ring detection, CID receiving and decoding, block list and EEPROM storage. I haven't done more than layout everything else as I've not made final decisions on features. If I decide to play an outgoing message I would need to incorporate a bigger EEPROM and DAC for playing that message. If the micrco needed a way to ring the phones I would need help to build a suitable ring generator. I'd also like suggestions for biasing the phones and detecting an off-hook condition. I don't have much experience with telephone systems.

[Bob Scott]

Ahh, surveys. I like surveys. The first thing I do is ask them how much it pays. They want it for free. So I tell them that their boss is getting paid to gather this data. You, the surveyor calling me is getting paid to gather this data, and I am expected to provide the data. I'm not going to be the only person not getting paid. I charge $100 per call if they are interested. Usually, they're not.

um, I should say "never interested".

[jimandy]

Yes, ltx71cm, we both have the same model in mind. In simplest terms, a box that sits between an answering machine and the house phone (which optionally -and usually- also has an answering machine). On non-ring through calls answer machine #1 catches the call with a message something like “Sorry your number is not recognized. Leave a message if you are friend, family or someone we should add to our phone list”. My experience is that almost all unwanted callers hang up when they get an answering machine.

I think this would be better called a “filter” system rather than a "blocking" system as no call will go unanswered if it is legitimate (even if a machine answers). This is much like the model used by an email junk filter that moves inbound mail to a “junk” folder if the sender’s address is not found in the contact list or, as you say a “white list”. And, as is often the case, some are really not junk at all, just an old buddy that got my address from a mutual friend.

Yes having a “ring through” code given to those who need access from a non-listed number would be nice but most of those folks have my cell phone number and would try it in an emergency. But this leads to a thought about the use of answer machine #1. Some of the more sophisticate units allow the use of “mail boxes” selected by the caller according to directions from the OGM announcement. Perhaps this could also be useful to direct “preferred” but unlisted callers to a certain mail box. This in itself would eliminate the pre-recorded junk-calls as they have no way of punching in a mail box code.

Also the ability to pre-program the unit via USB would be the killer feature. As mentioned before the JF Teck unit requires a tedious button pushing sequence that will be exhausting for entering dozens of numbers at one sitting. Since most of the numbers I want pre-set exist in my laptop’s address it makes sense to be able to just upload that info from that source.

In another topic I am exploring a voiced method of alerting us to calls that ring through (topic: “Record-Delay-Play sound-bytes”) but I think CID data injection is quite feasible. In yet another topic: “Looking for phone patch” you might get the hint that I want to play with that idea as well. The CID data is nothing more than old Bell 202 modem tones at 1200 baud in a prescribed message format and I have read that they will display on a CID box anytime during the between-ring, answer, talk sequence no matter when sent. This leads to some fun pranks with fake CID spoofing.

[moe]

I remember about 15 years ago Radio Shack had a caller ID unit that would allow you to reject up to 20 calls back then it was around $60.00 I don't know how long they made this unit but it did work well
Moe

[jimandy]

I am playing with an audio announcing CID unit (abt $35.00), exploring the possibility of recording it's announcement for delayed playback to the upstairs room with the phones that only ring through on approved callers.

The unit I bought has a loud and clear voicing of the phone number. But to voice the name of the caller one goes back and records it and it is apparently recorded with a lot of compression. When the voiced caller's name playbacks the quality is poor, almost unintelligible. Since I can't think faster enough to mentally translate the voiced phone number and, additionally, can't understand the voiced name of caller, this idea is probably not going to fly. The better plan it seems is to re-inject the CID data on the calls that are passed through. This is a bit beyond my experience level with micros and phone interface circuits.