Ethereal-dev: Re: [Ethereal-dev] Re: Getting signal from USB port

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From: Guy Harris <gharris@xxxxxxxxx>
Date: Tue, 01 Feb 2005 02:54:10 -0800
hasna dahnini wrote:

I don’t want to use Ethereal as an USB analyser. I just want to get Profibus signals through the USB port and analyse them on Ethereal.

OK, I don't know much about Profibus and Profinet, but I infer from what others have said, and from the stuff on the

	http://www.profibus.com/

site that Profibus is an industrial networking scheme that includes specifications all the way to the physical link layer, while Profinet runs on top of Ethernet. (The diagram on the page at

	http://www.profibus.com/technology/docu.html

indicates that Profibus runs on top of RS-485 and IEC 1158-2 as physical link layeer standards, and that some form of gatewaying is possible between Profibus and Profinet.

I'll assume that by "Profibus signals" you're referring to Profibus, not Profinet, i.e. that there's no Ethernet involved.

So:

And, I will decide on what format my signals will arrive on the USB port because the Profibus signals will come from an hard system.
Is that clear ? Can I use Ethereal for this application ?

...there are (at least) two issues I see:

	1) getting Profibus signals from some USB device;

	2) decoding the resulting information.

1) is a problem that is mainly a non-Ethereal problem.

If you can solve 1) in a fashion that lets you, for example, read Profibus signal information into a file, *and* that the file can be broken into packets - i.e., that Profibus is a packet-oriented protocol, and that you'll be analyzing packets rather than, for example, signal waveforms (Ethereal isn't a waveform analyzer) - then the only part of 1) that would involve Ethereal would be writing code to read the file, and then you'd write a dissector for Profibus that processes the data you'd read from the file.