HandsFree set + Phone line != Internet connection, yet

thegamefreak0134 · Post by **thegamefreak0134** » Tue 10 Oct, 2006 8:01 pm

This is a project I have wanted to do for some time now, but I lack the resources I need to make it happen. Remember that this comes from someone with little knowledge of hardware. OK, here we go.

You know how wireless handsets these days have that little port on the side for a handsfree set? I tested it out with some headphones I had put together, and you get a dial-tone and everything through them. Since they appear to have a decent quality signal at close range, I was wondering how hard it would be to do some nice wire splicing and hook it directly into a modem by converting the 2.5 mm headphone jack into a standard phone line.

After many tried and attempts, I feel there is something seriously missing from my attempts: a proper knowledge of the subjects. Mainly, the fact that while a phone line is a direct connection, causing the line to be "powered" by two wires, a handsfree set has this wire running back to base, which I always had to just leave hanging. I think what I may need to do is come up with a peice of hardware that can power both a phone jack and a 2.5mm headphone jack, and then send the signals back and forth.

The problem? I have no knowledge of hardware to do such a thing. I donn't want to buy something, I want to make it on my own, as sort of a learning experience, to improve my appreciation of those who work with this kind of thing on a day to day basis. (Plus, I could creade a calc modem this way... nah. Not fast enough. Scratch that.)

Can anyone point me to the resources I would need to get started on a project of this caliber? (Or is there a way to pull it off without having to build an adapter?) Thanks in advance for any help, I know this is a tricky topic.

-gamefreak

PS: Sorry for any typos, this was typed pretty quickly.

Post by **tr1p1ea** » Tue 10 Oct, 2006 8:20 pm

One problem is the fact that a modem is kind of a phone in istelf. It converts information from your pc into a phone signal and passes it along the phone line. If you pass something from your modem to your cordless phones, it is going through a conversion process twice, as the cordless phone would process whatever it recieves from the modem as well.

Im not phone expert, but it seems like you are going to have to open the phone up a little more.

Post by **benryves** » Wed 11 Oct, 2006 9:52 am

I don't think it would be practical to get the TI to act as a modem; it would no doubt require external hardware to be reliable enough to be useful (if possible at all). A better solution would be to just use the phone's built-in modem over IrDA or Bluetooth, which also gives the phone the ability to use GPRS for better speeds.

thegamefreak0134 · Post by **thegamefreak0134** » Wed 11 Oct, 2006 4:11 pm

(1) I don't really want to create a TI modem, that was a joke

(2) I would love to use GPRS, but this is not a cell phone, it is a house phone with a real dial tone.

*edit* Hey, cool. I'm an "extreme poster" now. Awesomeness! </offtopicishness>

Arcane WIzard · Post by **Arcane WIzard** » Wed 11 Oct, 2006 4:17 pm

Do you want to build this, or have this?

In the latter case, just buy a phone&modem combination. Better yet, buy a cellphone with internal modem.

Post by **benryves** » Wed 11 Oct, 2006 4:33 pm

thegamefreak0134 wrote:(2) I would love to use GPRS, but this is not a cell phone, it is a house phone with a real dial tone.

Sorry, I thought you were talking about the hands free kit on a mobile 'phone (the old Nokias, at least, had a 2.5mm four-pole jack - you could directly plug your TI into your 'phone).

thegamefreak0134 · Post by **thegamefreak0134** » Wed 11 Oct, 2006 6:34 pm

I definately want to build it, as I'm not sure the "have it" part works with my hardware, seeing as how it's not a cell. (I have a cell with this, but it does not let me do such things as dialing, because cell phones to my knowledge have no real dial tone.)

Anywho, disregard the intended purpose. I need something that takes the line-in and line-out on a 2.5mm headphone jack and turns it into a line-in and line-out on a phone jack. I figure this should be a simple process of mapping the data back and forth, I just don't know how the actual jacks work. (Right now I just have the wires and such, no jacks to play with.) Thus, if someone could provide me with the info on integrating these types of jacks into a piece of hardware, I could probably run from there. I need to do this so the connections are actually closed connections, my wire splicing apparently was not doing that.

-gamefreak

PS: The reason I want to do this is because I have no phone line in my room. Essentially, I want to use the wireless handset of our houseline to "create" a phoneline anywhere in the house, and this seems like the best way to do it.

Timendus · Post by **Timendus** » Wed 11 Oct, 2006 8:30 pm

benryves wrote:I thought you were talking about the hands free kit on a mobile 'phone (the old Nokias, at least, had a 2.5mm four-pole jack - you could directly plug your TI into your 'phone).

That's a pretty cool idea... Just make a little 3-pole to 4-pole 2.5mm jack converter, plug it into your Nokia and your calc, dial the number of a dial-up server on the phone and the calculator does the talking... That could actually be done I think, if the calc is fast enough to keep up with the server...

You could write a little GET application to download files on your calc from the Internet, or perhaps a simple POP client that downloads the headers of your e-mailbox..?

thegamefreak0134 · Post by **thegamefreak0134** » Wed 11 Oct, 2006 8:41 pm

<sobs of disbelief and frustration> I don't want to make a calc modem, seriously...</sobs>

However, if you can figure out how to make the converter work, please let me know, since it would be what I need.

DigiTan · Post by **DigiTan** » Wed 11 Oct, 2006 8:54 pm

As far as interfacing, you can use a UG telecom splice to wire your comp modem to the wireless headset. It's a button-shaped peice of plastic that can connect two wires without cutting or soldering. When you're done, just pull it apart and the original line is left basically intact--so the parents don't get mad.

That's assuming the headset can be disassembled. If your headset has as much bandwidth as the phoneline, this should do it. If not... (locks self in panic room)

thegamefreak0134 · Post by **thegamefreak0134** » Fri 13 Oct, 2006 5:52 pm

I would be opting not to dissassemble the phone. It is cheap plastic after all, and they would notice.

I hear tell from some other sites that it might be possible to run the handsfree wires (including the extra wire, which I discovered is a grounding wire) through a transformer from an older modem and then run the "line" from that. Problem is, I haven't the slightest clue what a transformer even looks like. Any info on this approach?

I also heard that the wires in the handsfree set (and possibly in the phone line) may be coated in such a way as to make this kind of splicing difficult. This was from a wary resource, and I'm not sure I trusted it. (He suggested holding the wires in an open flame.) Confirmation? Bashal? Your call.

As far as interfacing, you can use a UG telecom splice to wire your comp modem to the wireless headset. It's a button-shaped peice of plastic that can connect two wires without cutting or soldering. When you're done, just pull it apart and the original line is left basically intact--so the parents don't get mad. Laughing That's assuming the headset can be disassembled. If your headset has as much bandwidth as the phoneline, this should do it. If not... (locks self in panic room)

You mean go get a real wireless headset and take it apart? Never really thought about that... Good idea though, will go have a look now.

-gamefreak

DigiTan · Post by **DigiTan** » Fri 13 Oct, 2006 11:03 pm

The transformer is generally gonna look like the kind [url=http://www.altrancorp.com/audio_transformers.asp?id=45], but it could be even smaller. In a phone, it's typically going to be black & white and have "1:1" or "600:600" printed on it (if anything). Just make certain to unplug everything and maybe wear those medical gloves before modding them.

That weird splice-proof line might be Litz wire like they use in headphones. The splices have tiny blades and a conductive gel that ~might make it work decent. If it's Litz -- you're right, you might want to connect another way.

thegamefreak0134 · Post by **thegamefreak0134** » Mon 16 Oct, 2006 12:50 pm

The TI link cable is not like this, correct? I plan to use one of those, because it's a little handier, and I happen to have quite a few lying around.

Thanks for the info so far. I'll take a good look when I get home now, and see if I can find that transformer and info on how to make it work properly.