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DTMF, Phone Lines, Dialup, General Phone Link Hacks


Corrosion.
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I have been interested in DTMF tones and phone hacks since watching "History of Hacking Documentary" I learned about John Draper "captin Crunch" and about red boxing, blue boxing, etc.

I understand alot of this stuff nolonger works but I'm still interested in it.

I have a DTMF generator and I now use it to dial out simply because I can, I like it...

I was wondering and had some ideas, I've looked into it but have had problems figuring it out.

What I'd like to do...

Use a cordless phone to connect my laptop to a dialup connection,

I see this very very possible because dtmf tones will work over land lines and these cordless phones but....

I tried to connect a headset into our phone line, it has a volume switch on it, I noticed that turning the volume all the way up would cause the phone lines to be cut off thoughout the house but I could then use the line, my guess is I was pulling too much power from the line..

I also was unable to dial out using DTMF tones, I only had a 2 wire line to connect the head set, and weather I connected my mic or speaker I could not dial out, my guess is the two sets are for mic and speakers, so I'd need a 4 line cord correct?

Now on my laptop I'd like to be able to do this without modifying the cordless phone, so what would I have to hookup on my laptop in order for it to listen in on the tones and communicate?

I mean I'll have to wire up something into my laptops modem and it'll have to be able to communicate both in and out. (sort of how connections were made in the movie wargames)

and finally, I know that a cellphone does not allow you to play DTMF tones into the mic, it just dosn't work to dial out, but could I possible manually dial the dialup number and then once the computer has dialed the number (it wouldnt be connect yet) then I could then wire the cell phone into the computers modem and then could the computer talk to the cell phone? I'm thinking it would work if the connection was dialed manually first.

and yes I do understand that I could just use bluetooth and a data plan etc.. I'm experimenting and just trying to see if its possible, I want to do it this way..

I'll take any help/suggestions you've got......

In the mean time I'll keep on researching

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Use a cordless phone to connect my laptop to a dialup connection,

I see this very very possible because dtmf tones will work over land lines and these cordless phones but....

I don't know if what you want to do is possible. I think the basic idea is fine - the modem signal is sound, so it could be possible to pass it through a cordless phone. But - I think the line levels between a phone outlet, and a phone's headset connection are different - I don't think the modem and the cordless phone will be happy talking to each other.

Another issue that I think may come up is signal quality - there may be too much degradation in the phone signal by the cordless phone for the modem to be able to cope with it. (a bit of noise in the signal should be easy enough for the modem to cope with, it can drop to a lower speed to compensate, but a cordless phone may not pass all the frequencies used by modems - I am not sure the frequencies are the same range as DTMF signals, modems may use a wider range)

Really I don't know how hard it will be to make your project work. If you can find out if the line levels and the signal quality/frequency range is ok then I think you can make it work.

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Well, if it can be used without interference, then it should work, but too much noise on the line and you will just keep getting disconnected. Cordless phones would probably get so much interference(beyond the human ear, but mainly white noise, etc) from other electronics and such, it probably wouldn't work. Wifi and cell phone equipment digitally filters out noise, and in some cases generates its own in order to cancel out common noise signatures, but even wifi gets interupted by things like cordless phones, microwaves, cb's, baby monitors, etc. Like when you ahve DSl, they use filters to seperate the Voice from the Data portion on the same lines. Im not sure a cordless phone would work for this without this type of feedback filter.

Im just talking out my ass though, as I really have no idea if it will work or not. :)

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I can see why you want to do this, because of captain crunch and all. But, now-a-days it is really worthless. When there is free wifi outside what is the point. If you want to do this for fun than be my guest! And I guess if you were trying to do this over a wireless phone you would need to find a same frequency and something that can pick frequencies up on you computer. Or just attach your phone to your computer via usb and tether your connection. Good luck with your project!

cheers,

Destro

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Thanks for the help guys :)

I see what you mean by interference.....

But it "could" work, only tying it out will give an answer,

I'll try to get to the store today and pick up some phone equiptment to work with.

btw,

I've been trying to figure it out, what is the difference between phone lines that have 2 wire and those that have 4?

Because it seems phones work fine on either but then why have two types? It seems I'll need the four lines to properly try this out...

and if on a cell phone! Damn that would be sweet, (I have google voice and can call out for free, so just dial out to my access number to get online) I did run into a problem just thinking and think I have a solution. A computers modem wont even try to dial out if it cannot get a dial tone, I'll have to either generate, record, or download a dial tone that I could send into the modem so the computer would know it can dial out...

on a cordless this would not be an issue but with a cell phone it would... (cell phone would have more interference but hey maybe find an area with good signal we'll see)

I'll keep you posted on my project

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Thanks for the help guys :)

I see what you mean by interference.....

But it "could" work, only tying it out will give an answer,

I'll try to get to the store today and pick up some phone equiptment to work with.

btw,

I've been trying to figure it out, what is the difference between phone lines that have 2 wire and those that have 4?

Because it seems phones work fine on either but then why have two types? It seems I'll need the four lines to properly try this out...

and if on a cell phone! Damn that would be sweet, (I have google voice and can call out for free, so just dial out to my access number to get online) I did run into a problem just thinking and think I have a solution. A computers modem wont even try to dial out if it cannot get a dial tone, I'll have to either generate, record, or download a dial tone that I could send into the modem so the computer would know it can dial out...

on a cordless this would not be an issue but with a cell phone it would... (cell phone would have more interference but hey maybe find an area with good signal we'll see)

I'll keep you posted on my project

With 4 you can split a line to a different number, but really, you only need 2 for one phone number.

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and if on a cell phone! Damn that would be sweet,

I don't know for sure (I haven't tried it), but I think to use a regular modem with a cell phone (through the handsfree connection) will have a lot more trouble than using a cordless phone. With the cell phone, it is doing an analog->digital conversion (to send the digital data to the cell tower), and from what I understand the digital compression is optimized for voice, and will probably cut out important frequencies for a modem.

I did run into a problem just thinking and think I have a solution. A computers modem wont even try to dial out if it cannot get a dial tone, I'll have to either generate, record, or download a dial tone that I could send into the modem so the computer would know it can dial out...

on a cordless this would not be an issue but with a cell phone it would...

Your modem can probably be forced to ignore dialtone. I am not up-to-date on modem AT-commands, but I'm pretty sure I remember that at least some modems had an AT command to ignore dialtone - it's probably standard in most (all?) modems now.

I'd suggest trying to get it working with a cordless phone first, it should be easier than a cell phone. Then if you can make the cordless phone work, you'll probably be very close to making a cell phone work.

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zwl1.jpg

Acoustic Coupler. A decade ago (plus three weeks), I wrote how to build one for under $20.

http://stuff.h-i-r.net/articles/hir9/hir9-5.txt

Basically, with a 9V battery, you can take any two phones and make them "talk" to each other, or you can make a phone and modem talk to each other. Seriously, grab a phone cord and cut the red or green wire. Then hook a 9 Volt up to each cut end of that red or green wire. Hook it between two phones and you and your friend can talk to one another.

Now, to make a normal phone into an acoustic coupler, you have to use something to isolate outside noise a bit. I used cheapo suction cups. Old-school acoustic modems (and those classic payphone TDD terminals) used thick rubber cups. Either way, moving the microphone and the speaker to the outside of the phone's housing and getting some sound insulation around them to make a good acoustic connection is all you need to do.

The acoustic coupler shown strapped to my cordless phone is a professional-grade one from the mid-90s. It's a "Telecoupler II" by Road Warrior. Another one popular at about the same time was the the KONEXX Koupler. You could probably find either one on eBay cheap, but it's more fun to build it yourself.

Maybe I should go through and re-do my article with photos and better grammar. As has been mentioned in this thread a few times already, the usefulness of dial-up (much less crappy acoustic modem dial-up) is very limited these days with ubiquitous open WiFi and affordable broadband wireless (WiMax, EV-DO, EDGE). But hey, us retro-geeks have to hold on to something, don't we?

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vista doen't detect my modem :/ havn't tried it out on it yet so idk.. .lol gotta fix that before I can test

What kind of modem are you using? Most modems for phones (tethering) needs certain software. Are you using a phone or an actual modem?

cheers,

Destro

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