DTMF

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chava
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DTMF

Post by chava » Mon Dec 29, 2003 10:49 pm

Hi,
I want to start learning the DTMF methode.
can someone direct me to a web site where this subject is explained as simply as can be?<p>I want to connect an electric circuit to a nokia cel-phone so that the circuit will make a call, using the cel-phone. does anyone have know haw to do this ?
--------------------<p>Jukin Chava<p>E.Dove Israel
R&D
Jukin Chava<p>E.Dove Israel
R&D

myp71
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Re: DTMF

Post by myp71 » Mon Dec 29, 2003 11:07 pm

I beleive that the cell phones do not work like that using DTMF codes you would have to find a circuit that would activate (push) the buttons for which you would have to have a motor or connect up all of the wires from your circuit to your cell phone then when it is done dialing push send.
Try a pay phone for DTMF they work like that but Much simpler and less expensive ;) <p>Myp71

chava
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Re: DTMF

Post by chava » Tue Dec 30, 2003 12:21 am

NO!
what I want is to connect a programable chip to the phone, not through the buttons but through its connector.
I want to use the phone as a mediator between the programable chip to the cellular phone net
Jukin Chava<p>E.Dove Israel
R&D

rshayes
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Re: DTMF

Post by rshayes » Tue Dec 30, 2003 3:54 am

Try the National Semiconductor web site (www.nsc.com). The TP5088 data sheet and ap notes AN-444, AN-521, and AN-666 have some information on DTMF.<p>Phillips makes the PCD3311 and PCD3312 parts for this application. Other parts (vendor unknown) are the TCM5089 and TCM5589.<p>The keypads for touch tone phones use DTMF encoder chips. I would open up a cheap phone (one with with no special features) and see what was inside. Sometimes the keypads show up as surplus items.

myp71
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Re: DTMF

Post by myp71 » Tue Dec 30, 2003 8:56 am

OK!<p>You did not Explain that in your First post

bodgy
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Re: DTMF

Post by bodgy » Wed Dec 31, 2003 1:14 am

Two things to note on this.<p>#1 DTMF tones on a mobile phone have a slightly shorter duration than from a land phone or computer generated including DTFM chips. This accounts for the reason that using a mobile to retrieve messages from a answer machine or switch on devices, sometimes fails.<p>#2 AFAIK the only way you can persuade a mobile to activate a device is either by using one with a built in modem, or by haveing a modem device at the receiving end.<p>For info on general connecting bits and pieces to phones, especially using Pics, it may be worth looking at the ratring group on Yahoo who specialise in this.<p>groups.yahoo.com/group/rat_ring<p>Colin
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jollyrgr
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Re: DTMF

Post by jollyrgr » Wed Dec 31, 2003 2:47 am

If you want to adapt a cell phone so that it can be used like an analog landline phone, this has been done already. The device is a recharger/power supply/analog adapter cradle that connects a cell phone to a standard analog phone. (The same phones you would use with a standard landline.) The cradle can be connected directly to an analog phone or number of phones. If your house wiring is the standard two line configuration, and line two is unused, you can use the house phone wiring to control the device. Since this device works with standard analog DTMF phones, it will do exactly what you are attempting. <p>You dock your cell phone in the cradle and pick up a phone connected to it. You dial the analog phone and use the # key as the SEND key.<p>I know they make them for Nokia as you requested. Here is an example:<p>http://www.virtuvoice.com/cellsocket.asp<p>Also, here is a TechTV review of a similar device. (Wait for the splash ad to go away to read the article.)<p>http://www.techtv.com/freshgear/product ... 35,00.html<p>What a number of people do is use this type of device to make long distant phone calls. Numerous cell services have unlimited night and weekend packages with "FREE" long distance calling. While the quality of the calls are only as good as that of the cell phone calls, you can use a regular phone call to make the call; cordless or wired. And since the device powers and charges the cell phone you do not have to worry about the battery going dead. Plus you can connect a better antenna system to the docking station and avoid dead spots common with cell phone usage.
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chava
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Re: DTMF

Post by chava » Thu Jan 01, 2004 2:15 pm

Thank you all,
I'll reviewe all of it, and if thereould be a problem' I'll be here again
Thanks
Jukin Chava<p>E.Dove Israel
R&D

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