Re: DLT_request

[Weber René <rweber () baumer com>]

On Jan 11, 2017, at 11:42 PM, Weber René <rweber () baumer com> wrote:

> > We working at software for industrial cameras which are supported by the cameralink standard. We use Wireshark to 
> > monitor the control interface. We have implemented a solution similar like the u3v dissector and uses link type 
> > DLT_USER0.  The cameralink interface is basically a serial interface like rs232 uart.

> So this is for GenCP over a serial port, rather than GenCP-over-UDP?

I don't know a GenCP-over-UDP - where can I find some information about this?

CamaraLink is f.i. to find in https://en.wikipedia.org/wiki/Camera_Link  - at the schema you can see the serial to 
grabber and the serial the camera line.
The original cameralink specification you can download at 
http://www.visiononline.org/vision-standards-details.cfm?id=171&type=6. Without registration is it find at many other 
location (http://www.adlinktech.com/cn/products/MachineVision/pdf/CameraLinkOfficial.pdf)

The GenCP control channel is at the end a bidirectional serial channel like a pc uart (electrical are this two 
LVDS-signal lines). The signal data are asynchron serial frames with start, stop and data bit exactly like uart. The 
GenCP frames self are described in http://www.emva.org/wp-content/uploads/GenICam_GenCP_1.2.pdf.

> > But often exist this only inside the application and not as separate comport. The using of DLT_USER0 is not so 
> > comfortable, because the protocol at every user is at first to set to cameralink ... Therefore, I'm requesting a 
> > DLT_ value for this.  Please let me know what the proper procedure is for this or if you have any other 
> > questions/concerns.

> So do the packets in such a pcap or pcapng file start with the serial prefix described in section 1.5 "Serial Prefix", 
> followed by the common command data described in section 4.3 "Common Command Data", followed by the specific command 
> data for the command in question (section 1.6 "Serial Postfix" says there's no postfix for serial ports)?

correct. U3V in opposite to cameralink has a different prefix and a different endian order.

> (Presumably the same code can be used to dissect the common command data + specific command data for GenCP-over-UDP.)

perhaps


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