On Sep 28, 2010, at 12:56 AM, Agustin Figueredo Canosa wrote:
> I´m working with a link layer protocol using rs485 interface. I have
> created a dissector for my protocol and it works fine. But now I would
> like (if possible) to capture packets in real time.
>
> I think it´s not possible to capture live data from rs485 using wireshark
> directly but if anyone have worked in it I'll be grateful for any help.
Ultimately, Wireshark's ability to capture from a traffic source is dependent on libpcap/WinPcap's ability to capture from it, which is dependent on the OS on which you're capturing and/or the hardware used for the capturing. Modern versions of libpcap (for UN*X systems) and WinPcap (for Windows) support adding modules to handle various types of capture hardware and software (although they're modules compiled into the libpcap or WinPcap library, not plug-in modules loaded at run time).
On what operating system or operating systems do you want to do the capturing? What software does it have to support RS-485?
What sort of hardware do you have to connect to the RS-485-based network? An RS-485-to-USB converter, as you mention, or some other form of hardware (such as a serial transceiver)?
Do you want to capture traffic on an RS-485-based network that's neither sent to nor from the machine doing the capturing ("third-party" capture), or do you just want to capture traffic sent to or from your machine?