How Do I Filter Phone Calls on a Land Line?
An anonymous reader asks: "I have a telephone on a plain old land-line, with the option of subscribing to caller-id.
I would like to filter incoming phone calls, diverting them to either the handset or answering machine, based on whether the caller-id matches a list of trusted phone numbers.
Considering that many of today's land-line telephone handsets can display caller-id and store a list of favourite phone numbers, I don't think this is technologically difficult.
AI am not interested in: subscribing to a service provided by my telephone company. I would prefer the filtering occurred on my side of the phone line, or implementing a software solution on my PC. Frankly, that is overkill, and I don't want my PC turned on permanently. I would prefer something like a small, solid-state hardware device. Is there any such thing available?"
I beleive it's called a "wife". However, it's very very hard to pick these things up at a hardware store, and you can't get them off the internet (or at least the internet versions don't handle english language filtering all that well). I'd suggest that looking for more information on wives from slashdot is probably a waste of time.
An answering machine. Don't answer till you know who it is, and if they don't leave a message you probably didn't want to talk to them anyway.
"I use a Mac because I'm just better than you are."
http://www.privacycorps.com/products/?id=20
OK, you have a couple of options as I see it.
First would be to set up some kind of PBX. It's a little complex, but it would work. You could use Asterisk (I think that is what it's called) and some hardware (since I think it was designed for VOIP) and do it that way.
The more fun (in my eyes) and complicated way is to build it yourself. You could do this with a PIC micro-controller (or similar). You could put the little box you would make at the phone entry point of your house. When the phone rings you let the first ring through (so you know someone called). Caller ID is transfered between the 1st and 2nd rings so that is when the MCU picks that up. Based on that, it can power a double pole double throw relay. In the normally closed position the phone signals are routed to your house wiring. When a "bad" caller ID is encountered it simply powers the relay switching the phone line from being connected to the phones to the answering machine. Of course the answering machine could be anywhere if you can isolate it's phone jack from the rest (shouldn't be too hard).
Now there are a few little things to take into account here. First is that you may want to generate a ring for the answering machine so that it picks up on the 4th ring (or whatever) instead of the 5th because of the "lost ring". Second is that if you automatically send people to the answering machine unless the right caller ID comes across (i.e. the answering machine is in the normally closed position) then you'll need to make sure you have a way to force the relay to switch. You would want this even if you decide to pick up a call from the machine. When the main wiring is disconnected you could monitor the wiring to see if anyone picks up (you'd have to power it probably) and switch the relay if that happens. That way any time you pick up the phone you will always get the dial tone/caller. Having the relay connect you to the phone line in the normally-closed position is an important idea because you want it to be safe and let you use the line during a power outage.
It'd be a very cool project. You can find bits about how to do it on the web. For example, I once saw something about a guy who built his own TTL PBX. That project (which was rather well documented, as I remember) would be a gold mine for you.
If you do it, make sure to write it up and post it. I'd love to read it and I'm sure others would too.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
Well the obvious answer (at least to me) is Asterisk. If you don't want a "computer running all the time" build a small box, well.... tuff. Think Mini-ITX. You can put a small HD in in, and put it in a small case. If its only "diverting" calls it doesn't need much power or storage space at all and wouldn't draw much power (also, if you do it right - it could be all passive cooled).
Also - I'm sure no one wants to spend _that much time_ setting up Asterisk, so use TrixBox (Formely Asterisk@Home) instead.
snowulf.com
Microsoft released a 900MHz cordless phone back in late 1998 that had all the features you want, plus more. You could create a whitelist in the software and any phone call that wasn't in the whitelist wouldn't even ring the handset, but get diverted straight to voice mail. The phone supported voice dialing, multiple voice mailboxes, personalized rings and greetings based on the Caller-ID number. The software would automatically divert or block Caller-ID blocked incoming phone calls. The software even imported your phonebook from Outlook Express/Outlook.
Ok, granted, the phone was 900MHz, was quite bulky and the batteries were less than optimal. The one feature that this phone had that none (except PBXs) have had since, was total control of the hardware ringer. Because you had total control of the ringer, features became available (and controllable via software) that would allow you to force select incoming calls straight to voicemail or DND without ever being distracted by the ring. Of course, this product was soon killed and all support for updates to the software quickly killed, too.
The cheap Uniden dual-handset receiver that came free with my SunRocket service has a built-in phonebook, complete with user groups and different ring-tones. Set the default ring-tone to nothing/one quiet beep and put everyone you know into groups with a real ring.
No PBX, no software and service independent.
If you weren't such an asshole/idiot, you'd notice that someone else has indicated that such a device does exist: http://www.privacycorps.com/products/?id=20
Hook it up to a Linux box, and..... Yeah, that's all I've got.... It's probably possible though with the right kind of modem hardware and drivers.
In undeveloped countries, the consumer controls the market. In capitalist America, the market controls you.
What you want is to convert your home line to ISDN and use an old motorola BitSurfr device. You hand the calls over to the POTS ports on the device, and you can program it with AT commands. I think you can only set a small number of blacklist caller-id, or whitelist caller-id (i think 10) but it will serve as a nice filter. This will do what you want, and they can get dumped or a busy before the phone even rings.
It is EXACTLY what the poster asked for.
If it's a little overpriced then maybe you can get your techi friends togather form a startup, get some venture capital and produce a competing product at $50 that would just sweap the market.
--= Isn't it surprising how badly I spell ?
I had set up vgetty to answer calls after a number of rings that was based on the caller-id information, but that requires a modem whose voice capabilities are supported on linux. The idea was that 'Unknown Caller', etc. went straight to the voicemail, but everything else was allowed to ring four times. It's a simple and proven method.
Fnord.
What happens if someone on your whitelist is in some sort of emergency that forces them to use a phone that's not on your whitelist? Do you still want that urgent call that to go to the machine?
:-)
Personally I'd perfer not to ever have to answer unsolicited calls, and I'd also like the option of silencing the ring from certain callers at various times of the day. For example, nothing but "work" should ring my phone before 8am, nothing but "that girl I'm stalking" should ring my phone after 8pm, and absolutely nothing should ring my phone between midnight and 6am, unless a family member needs an immediate blood transfusion or something equally urgent.
The problem of course is that there isn't an urgent bit in the caller ID signal, and if there were such a bit, you could bet your last nickel that telemarketers would set it for every call, and it would have about as much effect as the boy who cried wolf.
With todays phone system and level of voice recognition technology, you could probably rig up something to autodetect voices and even determine whether it's a live human or a computer, and you could detect keywords and level of stress in the voice. Your voice system could ask questions of unknown callers. In essence, you could insert an audio CAPTCHA onto your end of the phone line. This is something I've dreamed about for years.
But again, you have to stop and ask: What would happen in emergencies? Would the person calling on behalf of your injured relative be willing and able to get past the screening process for a chance to talk to you (afterall, you might not even be home...)?
Idealism aside, I've concluded that right solution for me is to just pick up the phone when it rings. I've learned all the prerecorded telemarketer intros, so I can hang up on those in less than 1/2 a second. Sure, I could save myself some time if I blacklisted those intros, but I also don't have to make my friends wait an extra ring or two when they call me.
I probably don't want to talk to a person who screens calls like that.
I certainly won't talk to a machine. I might stumble over my words. Am I supposed to have a ready-made speech for you to record? It's not as if I could call back later to delete the message I left, or could determine if you got the message.
I may be paying long distance charges.
So, screw you. I have better things to do. I could talk to some nice and friendly people.
If it's truely important, the caller will re-dial after hanging up on your answering machine's greeting. Works fine.
Honestly, the "what about emergencies" arguement is as badly abused as "think of the children." My telephone is a resource for *my* convenience, paid for by *me.* If someone calls while I'm eating dinner with my family, the call is allowed to roll-over to the answering machine. If there's an immediate call-back, I'll probably interrupt what I'm doing. Somebody screaming into the answering machine in the next room would be a good clue too. Everything else gets done on *my* schedule.
It used to be that receiving a telephone call was a big deal - think back to the early 1900's. Nobody had phones. If somebody called you, there was probably large expense (money, time, effort) to place the call from the other end. That expectation persists to today, in spite of the ubiquity and low-value of most phone calls. The phone companies go to great lengths to maintain this perception of "high priority interrupt." They're in your face, and they want to stay there (but that's a completely different rant.)
Think of the children. They're busy eating their dinner and experiencing some family time. Call back later. (To address the original poster: get an answering machine; learn to use it; don't let the phone rule your life.)
1 sound muffled box containing
phone with answering machine
digital camera
laptop with OCR and RDBMS software
microphone
robotic hand
have the laptop listen to the microphone for noise (phone ring), the robotic hand should then hit the button on the camera which takes a picture of the LCD display on the phone showing the number, the image is transferred to the OCR software which returns the number, lookup the number in the RDBMS, if it's ok the robotic hand pushes open the lid on the sound muffled box "letting the ring out", if it's somebody you really don't want anything to do with the robotic hand lifts the phone and hangs up, in all other cases the phone is left to ring in the sound muffled box until the answering machine picks up.
Problem solved.
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My AT&T E5965C does exactly that. It's about $120 if you can catch it on sale.
Here it is at Amazon
Just to beat this dead horse into an ass:
"Hey, I'm hungry. I'd prefer not to eat at home. Probably takeout to the park or sitdown. Frankly, sitdown is too much like home, and I don't want to be inside. I'd prefer to go to the park."
If you said "let's go sit down at the burger joint", though the park is open and right next door, you'd be eating alone. I'd go to the park with someone else.
You're a sorry Anonymous retard Coward. You should eat alone for the rest of your life.
--
make install -not war
Everyone seems to be assuming that Asterisk = "regular PC running all the time." Why does this have to be the case?
I haven't ever set up an Asterisk system, but if you only needed a few lines and didn't need space for the huge full-length PCI cards that people use to bring in T1 lines and interface with lots of copper POTS extensions, couldn't you do it in a very small, low-power enclosure?
Set up a dedicated machine, like the set-top-boxes people use for DVRs. Micro-ATX, small case, fanless processor, and then run it off of a CF card or something. Enough people have done stuff like this to make it not exactly state of the art: I don't know what the system requirements are for Asterisk, but without any fancy psychoacoustic compression I can't think it's that bad to only manage one connection at a time. Certainly it ought to be within the realm of currently available low-power and embedded systems, even. In addition to routing calls, it could probably handle his voicemail and maybe even do other slick features like email recorded VM messages or play them back through the internal speaker. Replacing some existing devices, if he was so inclined, could substantially reduce the power burden of a new machine.
The OP has said he wants a hardware solution that doesn't involve his PC -- fine; that doesn't mean that it can't use some PC software, running on a dedicated "appliance" or appliance-like system. Just because it's a computer doesn't mean it has to look like a computer, smell like a computer, or draw power like a computer.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Hell, I'm a woman and I want a wife, too!
Just remember that anytime you're talking on a cordless phone, you're using a radio transmitter. While that might seem like a painfully obvious thing to say, it's amazing how many people don't get the connection between "cordless telephone" and "anyone with a scanner can hear everything I'm saying." If you don't believe me, find any good radio that has wideband receive and try searching from around 46.6-50 MHz for the older phones and 900-928 MHz for the new ones. I don't have a receiver that goes to 2.4GHz but I have no doubt that if you did, you'd hear lots of people up in that band, too (although decoding the digital ones might be non-trivial).
Whenever somebody brings up email privacy I just laugh -- we'll work on email encryption right after we figure out a way to convince people that broadcasting their conversations miles in every direction probably isn't a great idea.
Anyway, I recommend that anybody who uses a cordless phone as their primary means of communication should borrow a scanner for an evening and play around with it--see if you can find the frequency of your own unit. I know I'll never discuss anything sensitive on one ever again.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
The Caller-ID information is sent between the first and second ring, so the only way to avoid ringing is to drop the first ring 100% of the time. On the occasions where you do want to talk to someone, the time left to get to the phone is that much shorter.
I have an AASTRA talking Caller-ID box in my house. It does a great job of managing the phone. If the caller has intentionally blocked their Caller-ID information then it automatically answers after one ring and tells them I don't accept blocked calls (which are inevitably from telemarketers) and they should call back with Caller-ID enabled. For the rest, it speaks the phone number so I know who it is before I get to the phone. If it's someone I don't want to talk to then I just let it ring until the answering machine cuts in. It supports blacklisting so that people who annoy me don't even get to leave a message. One interesting feature is that I can record a short audio clip and have it matched to a specific name or number so that it will play that audio clip instead of speaking the number. That's a great help with things like payphones which I will always want to answer no matter what the number is (my telco sends "payphone" as the Caller-ID name).
Years ago (when I still had landlines) I had a box that intercepted all incoming calls without allowing the phones to ring. It delivered a simple message "Please enter your desired extension, or, if you do not know the extension, please dial "O" or wait on the line. Bleep!"
People were given one of several numbers to enter: 472 for family, 333 for work, 505 for businesses, for example.
472 always rang through with a particular ring, 333 rang through with another, 505 it would allow through or not depending on how I set the switch, with yet a third ring style.
Anyone who didn't have a good three digit number went to the answering machine, with no audible ring on any phone.
It was simple and effective, and anyone with the proper code could get through from any touch-tone phone.
People never had any problem with my giving them an extension number, as in "Call me when my car is ready, 206 555 0293, extension 505.)
I don't know if anyone still makes that simple box, but it would be worth checking for...
--
Tomas
Slap said card into a Linux or Windows box. I chose Linux but it seems asterisk has been ported to Windows, too.
Now grab asterisk. If you went with Linux you'll have to download and install the Zaptel drivers for the Digium card, too. I haven't had much luck with the Debian packaged Asterisk and prefer to compile it from the CVS tree. Once you've got asterisk installed you can modify your extensions.conf file. Make some local extensions (You can use your FXS phone and a SIP soft phone like Linphone to test these.) Now you can do ALL SORTS of fun stuff. My home setup has a little voice menu system that asks you if you're a telemarketer and then asks you to dial 1 or 2 for myself or my room mate. If we don't pick up, the call goes into a voice mail system very simlar to what I have at work.
Eventually I plan to sign on with a VOIP service and keep the landline only for inbound calls and 911 service. You can also route local calls over a landline and long distance calls through a VOIP provider (or one of those 10-10 serivices if you prefer using one of those.) You can also set up speed dial keys for any combination (#1 on my phone gets you Abo's Pizza in Lafayette.)
I suggest that you keep an actual non-wireless phone plugged into one of the other landline ports in the house -- even if you're on a UPS, a protracted power outage could end up leaving you with no way to call 911. Having an old non-wireless phone around is the safest thing to do -- they draw voltage off the phone line to work, and that usually stays up. Just make sure you don't have to plug the phone into anything other than the phone line and you'll be good to go.
Asterisk takes a fair amount of configuring and it can be intimidating at first, but the flexibility it offers to the home user is unparalleled by anything else in its price range. For a home user, anything coming even close to it would be well out of the price range of most people.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
and it's offered by verizon nowv erizon.com
http://www.google.com/search?hl=en&q=iobi+site%3A
every day http://en.wikipedia.org/wiki/Special:Random
Just as one example, there is more to a caller then "good number" or "bad number". There are actually 3 choices on the machine: 1= do not send to answering machine and do not ring the phone. This would be the ex-wife option. 2= send to answering machine but do not ring the phone. This is the current wife option. 3= ring the phone first and if no answer then let them leave a message. This is the current girlfriend option.
Second, TIME and DATE are sent by caller ID, you don't set them in the machine! Arrgh!. I don't have the time or patience to retype the whole (badly written) user manual here, but after having this device for 8 months I bought a second one just to keep in stock in case the first one needed service I would have a spare. Having this box to keep dimwits from ringing the phone is almost as good as Sex. Now, when the phone rings, it is guaranteed that the caller is someone I want to talk to. That's as good as getting only love letters in the mail, no bills or tax forms or junkmail.
This is quite a first I've seen on an Ask Slashdot. Someone's question is a very detailed list of the specifications of what they want a technological solution for. That's almost a miracle in itself that the question made sense, was slightly challenging to answer and research, and didn't involve asking for legal advice. Most amazing of all was that someone actually provided a link to a device to purchase that seems to do exactly what was asked for and more. Bravo!
OK, everyone, the Ask Slashdot category has been redeemed this once. I ask all Slashdotters to study this occurrence and try to implement these features on future iterations of Ask Slashdot.
We may experience some slight turbulence and then...explode. -Capt. Mal Reynolds