WIZnet Developer Forum

Networking issues


I am planning on using 70+ WIZNET modules WIZ140SR for a test setup.
We have made a custom board that contains an ethernet switch and the WIZ140SR.
When we boot it up, we notice that about 50 % does not want to connect to the network and the others do.
The ones that do not, they have the LED of the module blinking during the firmware startup and configuration and then stopping with blinking. Then I notice that the TX/RX of the IP port continue to move around in the DC level.

The ones that work, work 100% perfectly on all sockets and all locations, the ones that do not work … don’t work ever.

What can be the reason, how can I debug further …

Thank you for the pointers,

kind regards,


I think we need to check the schematic. Please send us email your schematic included Gerber, layout file and We’ll check it .

email: scott@wiznet.io, ekkim@wiznet.io

Dear Irina,
Thank you for your reply.
I will send the information to you.
Thank you.
Kind regards,

Have you ever sent an email to us? I haven’t received any email yet.

I’m sorry. I just checked your mail because it’s in junk mail.
The hardware engineer will give you an answer as soon as he confirms it.

Hi Irina,

No worries, thank you for the quick reply.

Kind regards,


this topic can be closed, it appeared to have been a termination issue. The issue has been solved.
Thank you for the support.
Kind regards,

I’m glad that your issue has been resolved. If there is any other issue, please ask me a question.

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