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?"

Comments

The same way everyone else does

[0racle]

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.

Re:The same way everyone else does

[maelstrom]

A wise man once said as simple as possible and no simpler. I like this solution :)

Re:The same way everyone else does

[Alien Being]

Not quite right. I think the real question is which answering machine has the ability to ring or not-ring based on caller-id info. I wish my own answerer could do that. It should have these options to control whether the phone rings:

Ring/don't ring for blacklisted callers
Ring/don't ring for whitelisted callers
Ring/don't ring for new but identified callers
Ring/don't ring for unidentified callers

It should have similar modes controlling whether or not the machine will accept a voice message. That should all be simple to implement in a device that connects like a regular phone (in parallel). When reviewing the incoming calls, it should be a one-touch operation to specify how the machine should handle future calls of the same type.

The super-duper version should have the ability to sit between the phone line and other devices (series) and use a speech synthesizer and recognizer (or dtmf decoder) to allow control from regular phones throughout the house. e.g. A call comes in, the phones give a single short ring as the machine announces itself to the caller. If a person picks up a phone, the machine tells him whatever it knows about the call and asks whether to hangup, connect, or take a message.

Re:The same way everyone else does

[LordNightwalker]

"Hi, it's Mike. I'm not in, so leave your message after the beep" costs you less 5 seconds of your life. If the answering machine is set to pick up immediately, it will even *save* you time, because the machine will have picked up before I have the time to walk over to the phone and pick it up manually.

On the other hand, you might be that pesky asshole I don't really want to talk to. You know, the one that won't shut up, the one I can't possibly end a phonecall with in less than 20 minutes without being rude.

So let's do the math again:

• You call me, leave a message after the beep. You lose: 30 seconds total, 45 tops.
• You call, I pick up, you're the talkative asshole. I lose: at least 5 minutes, possibly half an hour or more.

My time doesn't have to be more important than yours to justify my screening of the calls; I stand to lose more time than you by picking up the phone. You can whine about it all you want, that won't change the facts.

Besides, my time might very well be more important than yours, and probably is. Remember that you're the one picking the time of the call, not me. You time the call to coincide with a moment you're not doing anything important anyway, unless it's an emergency call. Chances are I'm actually in the middle of something. Are you trying to tell me that whatever it is you want to tell me is more important than anything I might be doing at that time?

If whatever you want to tell me is important enough to interrupt my shedule for, it's important enough to leave a message for. If you can't be bothered to interface with a machine for 20 seconds to help me manage my time, I can't be bothered to interrupt my shedule to talk to you.

Handset.

[jfisherwa]

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.

Easy

[Anonymous Coward]

I own a box that does that. I can't recall the name, but SmartHome.com sells a $100 "Caller ID Manager" that appears to do the same thing.

I think of it as a firewall for the phone. Mine even does that three-tone "disconnected" tone for egregious fun.

It goes both ways.

[r00t]

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.

Re:It goes both ways.

[jon doh!]

um..is it that hard to say "it's me [$yourname], its [not] important, call me back."?

Re:It goes both ways.

[lawpoop]

"Am I supposed to have a ready-made speech for you to record?"

Look, this isn't a Senate hearing. Just say who you are, when (approximately) you are calling, and what you are calling about, and what I should do in response to your call (i.e. call the police, call back immediately, call back when I get a chance, wait for your call...)

Something like,
Hey, it's r00t, it's about five-thirty -- I was just calling to see if you wanted to go to the game on Saturday... I had an extra ticket... Gimme a call when you get this message. Bye!

" 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."

Are you calling to communicate, or to socialize? If you call and say "call me back long distance", you might get the other person to call you back and pay the long distance toll.

Re:It goes both ways.

[lawpoop]

"If you won't pick up the phone, why did you give out the number in the first place? That was rude. You faked me out."

I certainly wouldn't have given you my number to be at your beck and call at any time you please. When you call, I'll pick up if I'm not busy and I feel like socializing. Since you probably have no idea what I'm doing at the time when you call, you wouldn't know whether or not it's a good time. Maybe I'm the the shower, in the middle of a task, having an argument with my spouse, or even driving, in the case of a cell phone.

If I didn't have an answering machine or caller id, I wouldn't even know you called if I wasn't able to pick up. At least with an answering machine you have the opportunity to let me know that you called, and what you wanted to talk about.

Re:It goes both ways.

[r00t]

When talking to a human, I can hear the response. I immediately know if my words have been misinterpreted. The machine faithfully records something that may be taken wrongly, perhaps with disasterous consequences.

A human doesn't need a ready-made speech. There is interaction. The feedback helps to form the message.

Re:It goes both ways.

[lawpoop]

"If you choose to give out your phone number, then I nearly expect that you will be at my beck and call any time I please. You made the choice to give out your phone number. Live with it. It's rude to fake people out. " You really think that when someone gives you their phone number, they are really expecting to become your personal genie ( "You rang, master?" ) just because they gave you seven digits? I think you have an unrealistic perception of what relationship you are establishing when you get a phone number.

I think you are probably the only one getting "faked out" when people hand you their number. I haven't met anyone who thinks like you.

So you don't like call screening. You don't like talking to machines and leaving messages. Can you imagine that you might actually need to leave a message for someone? That an answering machine might actually convey information?

You do realize that you aren't actually talking to a machine, right? That box isn't acutally listening to you, you know -- it's just a recording device to give a message to the intended recipient. You might think of it as a delayed conversation, or a verbal letter -- a 'voice mail', so to speak.

When you were young, you lived in a different world. When the phone rang, you had to rush to wipe your ass so you could pick it up -- if you missed the call, you would have no idea who called, why, or how important it was. Nowadays, we have caller id, answering machines, and voice mail. We don't *have* to rush, so why should we? Why should I develop hemmoroids hurrying my bowel movements because Right Now works for you?

You took the damn time to call, you must have had something to say, even if it's just "hey, calling to chat" so leave a fricking mesage!! I've got better things to do than wait around for people to call.

Re:It goes both ways.

[Sloppy]

If you choose to give out your phone number, then I nearly expect that you will be at my beck and call any time I please. You made the choice to give out your phone number. Live with it. It's rude to fake people out.

The problem here is due to different interpretations of what a phone number is for. Some people give out phone numbers so that they can be communicated with. You think people give out phone numbers so that they can be communicated with interactively.

Screening calls is rude. I avoid calling people who do this.

Perversely, by choosing to rigidly interpret it as rude, you are gaining the benefit of call-screening technology. You are now freed from having to talk with people who you probably wouldn't get along with anyway.

If it's important, they'll call back

[Migraineman]

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.)

Re:If it's important, they'll call back

[bahamuut]

Look, maybe this doesn't happen to folks very often, but as someone who doesn't currently own a cellphone and uses public transportation and payphones quite a bit it is a valid scenario:

you're stuck somewhere and the last bus has already run it's route. It's cold or rainy and you've already walked five to ten miles and are feeling really tired/hungry and like the world doesn't give two shits about you. you're down to your last fifty cents and you've decided to call one of your so-called friends that you think is most likely to help you out. you dial the number hoping, praying that they'll pick up, and the call goes directly to voicemail, robbing you of the last bit of money that you have. My current life situation has helped to put things in a maybe 'unique' perspective, but I think that we just need to develop systems or just learn ourselves to handle unwanted calls in a humane, yet stern manner making it clear that solicitous repeated calls are unwanted, yet leaving the line open for our friends and family that might be on payphones or in unusual situations and in dire need of our help.

Re:If it's important, they'll call back

[hab136]

yet leaving the line open for our friends and family that might be on payphones or in unusual situations and in dire need of our help

So you want people to put up with the certain daily annoyance of telemarketers (new ones will call regardless of how stern you are with previous ones) on the slight chance that we have a deadbeat friend who might have to spend a night outdoors? Even in your contrived scenario, nothing is stopping said deadbeat from leaving a message with his location and situation, then repeatedly collect-calling (since he apparently has nothing better to do). Collect calls are automated these days; they won't get tired of you calling the same number over and over.

My little brother has called me from jail more than once, usually around 3am (thanks bro). I don't pick up on strange numbers, but when I listen to the message a few minutes later, I drove down and bailed him out. Big deal. (Tip for you: it takes a while to bail someone out. Bring a book.)

I can't think of any situations where you only have 1 phone call, can't collect-call, and absolutely have to talk to someone as opposed to leaving a message.

Besides, we don't have to - and shouldn't - base our lives around .001% chances.

Re:If it's important, they'll call back

[ehynes]

Should we stay home all of the time too so we're there to answer when this one in a million phone call occurs?

Re:You want one of these.

[plover]

Cool idea, but bad user interface.

It should have five buttons: one button labeled "BAD NUMBER" and a different button labeled "GOOD NUMBER". A scroll up and down button and a "FORGET NUMBER" button would complete everything it needs. No "save", no "select", no "menu", no "timer", no "dialing". It doesn't need time and date (good god, not every device need a fracking clock these days!,) and it doesn't need to be "preprogrammed". It just has to route junk calls to the answering machine, not "manage my caller ID lists."

Basically, what I'm saying is if my mom needs me to come over and figure it out for her, it's too complex. This is really close to a great product. Simplify the interface and it's a winner.

Re:Telephone Hacking for Fun and Proffit

[austad]

Asterisk will do what you want. You can set up rules in your extensions.conf file to filter on the incoming caller id. Send everything unknown to voicemail, and you can create a list of known numbers that will be forwarded to your phone. I'm running it at home now and it rocks.

If you want an easy way to get started, search for Asterisk@home. It's a distro that just wipes the box clean and installs linux with a fully functioning Asterisk install. About the hardest part of getting it set up is figuring out the concept of contexts and how they work.

The best part about having your own Asterisk server is that you can use a softphone on your laptop and make and receive calls through your home phoneline from anywhere in the world. I was just in Jamaica and used it to make calls back home for free.

What about a STB-type system?

[Kadin2048]

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.

Classic

[coyotecult]

Hell, I'm a woman and I want a wife, too!

No Problem

[Greyfox]

Pick up a Digium FXO/FXS card. Technically you only need the FXO module (The bit that plugs into the landline) but unless you have a SIP phone handy you'll need something to plug a phone handset into. You could try using a software-only phone but those things seem to be a bit of a pain in the ass. If you have more than one landline you can pick up a variety of combinations, such as FXO/FXO/FXO/FXS or FXO/FXO/FXS/FXS. The card I have supports up to 4 modules and you can mix and match modules to your heart's content. Note that you'll need to plug a plug from the power supply into the card if you plan to use the FXS module. This provides ring voltage to the FXS modules.

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 believe it's called IOBI

[way2trivial]

and it's offered by verizon now
http://www.google.com/search?hl=en&q=iobi+site%3Av erizon.com