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How to input a signal to a ADSL modem (in phone line input) that such a simple sinusoidal signal and get same signal by computer ? ADSL modem connected by network cable and usb cable is The software to do this ? Is it possible to do the matlab help ? thank you

ADSL modem work like a AtD (analog to digital) converter , Copper telephone lines carry analog data and by ADSL modem that analog date convert to digital data !

kapitan
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    ADSL modems work with high frequency signals (above audio) and I would expect them to be pretty much optimised for a single task and difficult to repurpose. – RedGrittyBrick Oct 20 '13 at 11:39

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The following diagram block diagram taken from the xDSL Modem/DSLAM page at Texas Instruments illustrates what you'll find in a typical ADSL modem:

enter image description here

So while your general assumption that they contain an ADC and can interface to a PC via USB or Ethernet is correct a few likely challenges are:

  • There is some coupling and filtering on the analog side of things. That may be possible to bypass if you know what you're looking for but even that can be difficult with multilayer PCB designs.

  • The ADC and CPU may well be either proprietary ASICs or otherwise require an NDA to get access to the datasheets. Even if you can find that information tracing how everything is connected together is likely to be very difficult.

In general while not impossible it's likely to be far easier to either purchase or design something for this purpose. You'd really need to state your requirements but some fairly easy to use data acquistion solutions at the lower end of the spectrum are only $20 or so.

PeterJ
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  • i Think by using MATLAB Data Acquisition Toolbox it is possible i check Data Acquisition Toolbox by laptop sound card and it is good response but sound card sample rate is about 8K that is very small . is it way to use ADSL modem as a input device for Matlab Data Acquisition Toolbox ? – kapitan Oct 20 '13 at 13:25
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    You won't find an off-the-shelf drivers to do it and it would be really complex. While a nice idea in one way using existing hardware unless you're a real expert in those areas probably not practical. I'd probably forget the idea to be honest and either design or buy something more suitable. – PeterJ Oct 20 '13 at 13:42