Caller ID Privacy Manager

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techie2
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Caller ID Privacy Manager

Post by techie2 » Sat Aug 06, 2005 1:02 pm

I've seen units available on the market that will decode the caller ID and route incoming calls to an answering set, ring the phones, or disallow a call.. I am wondering if anyone has been working on a home brew version of the same thing, perhaps using a PIC? I'll attempt to add a link here.<p> web page

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Re: Caller ID Privacy Manager

Post by dyarker » Sun Aug 07, 2005 10:48 pm

If I remember correctly, Caller ID is phase shift modulated 1200bpS, between first and second rings. Demodulating the data would seem the hard part to me. Either a 1200bpS MODEM chip, or maybe some PIC ADC code.
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Re: Caller ID Privacy Manager

Post by jimandy » Mon Aug 08, 2005 5:38 am

Somewhile back I had an interest in such a project (using a Stamp). The plan was to have a buit in bank of allowable caller's numbers or, if the caller was not in memory, they could optionally enter a code and the call would pass through. Otherwise the call was routed to the answering machine. I ordered a CID-on-a-chip decoder, I think it was from Exar. The project is still sitting there in the "round tuit" box.
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techie2
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Re: Caller ID Privacy Manager

Post by techie2 » Mon Aug 08, 2005 9:31 pm

Dale Y: I didn't explain myself very well as to what I really would want do. You are right about the 1200 baud phase shift modulated signal. I would use a decoder chip to handle that part. But to use the data, display, store, etc. would require a microprocessor. <p>Jimandy: I have a "round tuit" box too.. Seems to get filled up with parts and "dreams" that never materialize. <grin> What you describe is getting close to what I am interested in. <p>I also realize that there is software available to use with a PC to do what I would like to do. However I do not want a "power hungry" PC running just to screen my phone calls. <p>My ideal caller ID screener would work (similar)to one pictured on that link I put in my first post. However I see a few things I would like to do differently. I would like to be able to feed the data from it to a PC to analyze on an as-needed basis.<p>Also instead of programming the unit the way they do, I would prefer to program it via a PC. The only time it would need to be connected to a PC would be to make program changes or to review a list of calls which have been "processed". It could be a simple serial port connection to the PC when needed, or maybe a flash memory card could be used & removed, read & programmed through the PC and then put back into the device. This memory card could hold not only the data for how the unit would direct calls, but also the record of decoded calls. However, that could be a challenge to develop. <p>I would be interested in hearing from anyone who has built anything using a caller ID receiver chip and a microprocessor of any sort. I'm just trying NOT to reinvent the wheel. <p>Telemarketers: The crabgrass on the lawn of life.

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Re: Caller ID Privacy Manager

Post by Newz2000 » Tue Aug 09, 2005 8:14 am

I worked with a system just like you wanted... it was made by Lucent and called a "Definity ProLogix;" it cost about $150,000. It had the added feature that it could route phone calls not only by the caller id information but also based upon what type of place the call originated from (for example, a prison or a large business). But if you think a PC is power hungry, you wouldn't like this one at all. ;) <p>Seriously though, I saw a group of telephone projects related to the PIC here: http://www.piclist.com/techref/member/r ... /index.htm<p>They have a lot of information on caller-id.<p>What you want is a database/look-up table combined with a telephone switch. I don't know how to do that on a PIC, but based on the small memory available it would likely require using external storage if you'll use more than a dozen or two telephone numbers. Then you'd need additional hardware in order to route calls to a voice mail box vs. a telephone. Sounds tricky.<p>Considering the wealth of PC software out there for this, I'd be tempted to use a PC. If you want something compact and non-power hungry, why not a mini-itx or nano-itx based system? No moving parts, lower power requirements (something like 10 watts), and very small (the size of a deck of cards in some cases).<p>You can often find 2nd hand systems for < $50 and many have a PCI slot which will accommodate a modem or an FXO card. <p>You could then run a system like Asterisk which is a PBX on a PC. It includes built-in voicemail, voice over IP, advanced routing rules and it's completely free. Just food for thought.<p>BTW, that privacy corp box is amazing if it lives up to its marketing claims. I'm sure its a custom ASIC in order for it to be so small.<p>[ August 09, 2005: Message edited by: Matt Nuzum ]</p>

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Re: Caller ID Privacy Manager

Post by jimandy » Tue Aug 09, 2005 8:59 am

As I thought out my proposed CID monitoring system this is where I got hung up (pardon the pun).<p>The definition of a blocked call was one that did not ring the phones in my home (scattered over three floors). Now to do that, the unit must intercept the call before ringing the phones. This required the unit be installed on the entrance side of my in-house network.<p> The CID tones come in between the 1st and 2nd ring. After determining that the call was valid, the system would then connect the outside line to the home network and allow the telco ring signal to ring all the phones. At this point, however, the CID signal was history so my CID units all over the house would never display who was calling. So even though the fact my phones rang told me it was an "approved" caller, I still wanted to know who it was before picking up the phone. Sometimes I just don't want to talk to my sister-in-law!
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Re: Caller ID Privacy Manager

Post by kheston » Tue Aug 09, 2005 9:19 am

It's much more than you're asking for, but you might check out www.asterisk.org.<p>Asterisk is an open-source PBX system that can be configured to act as a full-fledged call router/voicemail/voip system. I got started with $14.99.<p>I've set up a single-line FXO device to be a call screener. Depending on your call-id, I either let the phone ring or send callers directly to voice mail. I'm doing very little of what Asterisk is capable of.<p>If I spent a few more bucks, I could ring and route to my house phones using an FXS interface. Not quite there yet.<p>Hope this helps.
Kurt - SF Bay

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Re: Caller ID Privacy Manager

Post by techie2 » Wed Aug 10, 2005 10:16 pm

Thanks Matt, Jimandy, and Kurt: <p>Matt:
Thanks for the link. Those PIC related projects look interesting. I thought that what I wanted to do could be done with a PIC.. I just don't recall having seen any projects in N&V about caller ID using a PIC. I have ALL issues from the very first one. <p>I've worked with computers and repaired a few, but most MOBOs have been the ATX form factor. I knew of the micro-ATX, but did not know about the ITX. <p>I see Kurt also mentions (and appears to be using) the Linux-based Asterisk system....
-------------------------------------------------------- <p>Jimandy:
I see your problem. My unit will be set up the same way, ahead of ALL of my phones.<p>I would want(somehow)to regenerate the CID signal and send it out to the phones on "approved" calls. I have no idea how difficult that would be, but there must be a way.<p>What I may try (since my phones don't have the CID display built in) is to use a second pair of wires and feed caller ID units directly from the line. Seperate jacks for the caller ID units.
You know the telco "inside wire" has at least two pairs. If you only have one line coming in, you probably have an extra pair of wires to use... I know I do...
------------------------------------------------------------ <p>Kurt:
I visited that web site. Had never heard of it. And I've had no experience with Linux. I am confused on how you got started for so little money. I must be missing something.
But it appeared as if I would need some of their hardware. Maybe that is only if you want to route calls?<p>What hardware are you using to interface your incoming telephone line to the PC?
A voice modem?
Also, I failed to see the minimum requirements for the PC in order to run the software.<p>[ August 11, 2005: Message edited by: techie2 ]<p>[ August 11, 2005: Message edited by: techie2 ]</p>

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kheston
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Re: Caller ID Privacy Manager

Post by kheston » Thu Aug 11, 2005 8:11 pm

It looks like you can get a simple answering machine going for under $10 provided you have a PC lying around. I'm using an old Pentium 90 with 64MB RAM. Works fine.<p>Check out:<p>Digium<p>for a ready to run FXO card (X100P - $25.95). Or if you have your soldering iron handy:<p>Howto
-and-
laptops4me<p>The latter/homegrown solution costs less ($7.92).<p>The Asterisk driver is written to work with a standard winmodem (intel 537 chipset based card sans a couple of resistors). The winmodem becomes an FXO device into which you plug the from-the-phone-company RJ11 end into. You are then able to route it to your interior phones with one or many FXS cards if you like (for Voip only, an FXS device is all that's required). FXS devices start in the $100 range. I didn't need an FXS device as all I wanted was an answering machine on steroids. Hence, I got off cheap.<p>The current SuSE Linux distribution comes with "answering machine" software bundled. I think it's just Asterisk with a ready-made configuration file and setup tool. However, it's the latest and greatest Linux and will probably require a little more RAM and could do with more horsepower than I'm running. Nonetheless, it may be easier for you. I was able to use a smaller Linux bundle and a custom Asterisk, but it took some doing...certainly not for the faint hearted. I'm a programmer-nerd and started using Linux a few kernel releases ago so I've got a higher pain tolerance than most windows/mac users.<p>Do some Google searches on "winmodem asterisk" or "asterisk voip". There's lot's of info out there.<p>Have fun! :D<p>[ August 11, 2005: Message edited by: Kurt Heston ]</p>
Kurt - SF Bay

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Re: Caller ID Privacy Manager

Post by jimandy » Thu Aug 11, 2005 11:07 pm

techie2: <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> I would want(somehow)to regenerate the CID signal and send it out to the phones on "approved" calls. I have no idea how difficult that would be, but there must be a way <hr></blockquote>
----
Hmmm. Maybe there's another way. If the CID comes in consistently (time wise) following the initial ring then the MPU could connect the house side following a prescribed time interval triggered by the ring signal, but just long enough for the CID display units to register. It disconnects again (during the 2nd ring signal) which gives the MPU time to decide if it's an approved call. No regeneration needed.
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Re: Caller ID Privacy Manager

Post by John Brown » Mon Aug 15, 2005 11:02 am

Here in the UK the CID is sent before the first ring. Although it is preceded by a line reversal. Assuming you have some sort of micro involved, you could save the bit stream and then re-modulate it to send it to the selected phone. The modulation part should be much easier that the de-modulation.

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techie2
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Re: Caller ID Privacy Manager

Post by techie2 » Tue Aug 16, 2005 8:12 am

Jimandy:<p>I think you've got a good idea there. I have a timing chart from Motorola for their MC145447.
The chip may be old, but the timing of signals remain the same. It appears that if you could set up a timer (triggered from the first ring cycle) to operate a relay, you could build it with a pot to allow adjustment. You would need a timing period of 1.5 seconds after the end of the first ring cycle, and then have it operate a relay to disconnect your phones to the rest of the house. It appears that you have a 500 milliseconds after the caller ID data is sent (before the second ring cycle. In that time if there is a signal from your unit for "unwanted" calls, it could be used to tell the timer to go ahead and operate the relay. Sounds like simple logic.
Signalwise you want the relay to operate about 2 seconds after the ring cycle "AND" only on unwanted calls. If the call is valid (wanted)the timer would need to be reset so it does not operate the relay. (something like that) Sounds like a job for the 555 Timer that seems to show up so often in N&V Q&A comumns.

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techie2
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Re: Caller ID Privacy Manager

Post by techie2 » Tue Aug 16, 2005 8:18 am

John Brown:<p>Quote:
Here in the UK the CID is sent before the first ring. Although it is preceded by a line reversal. Assuming you have some sort of micro involved, you could save the bit stream and then re-modulate it to send it to the selected phone. The modulation part should be much easier that the de-modulation.
=====================<p>I'm glad to know that. I've been looking at the RAT_RING egroup on Yahoo. I think it comes out of the UK. So I will need to be aware that the code for the microcontroller that they use will probably not match up... for here in the US. Thanks.

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Re: Caller ID Privacy Manager

Post by John Brown » Tue Aug 16, 2005 2:46 pm

Indeed. I believe the modulation scheme is slightly different as well.

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Re: Caller ID Privacy Manager

Post by jimandy » Tue Aug 16, 2005 5:35 pm

techie2: <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> It appears that if you could set up a timer (triggered from the first ring cycle) to operate a relay, you could build it with a pot to allow adjustment. <hr></blockquote><p>Ah ha. T2, we're sort of in accord on this. Except I would not use an analog (as in 555 time with a pot) to measure the delay but I would use the MPU to count cycles or whatever. In the case of a Stamp, call an instruction with a time parameter which basically does the same thing.
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