Can't start-up WIZ108SR


My company recently has acquired four WIZ108SR modules.
I am supposed to configure them to be used in a project, but I could not locate none of them with the Configuration Tool (v1.4.4.1).

Checking the modules, I noticed that its Ethernet port is apparently not working at all. Upon connecting the Ethernet cable in the module, none of the RJ45 LEDs blinks, and I tried with dozen cables and Ethernet switches, with no success.

I’ve checked pin 8, and it’s blinking every one second, indicating that there is No-PHY link estabilished (as stated in the User manual), even with the Ethernet cable connected.

Any tips? Is there any other configurations or steps I’m forgetting to do in order to start up these modules?

Thanks in advance.

Fillipe Couto


WIZ108SR is RS422/485 operation module.

Configuration tool location is below link

And I curious your 108sr H/W version.

And where did you buy?

It is 3.3V operation.

more detail information is refer to usermanual.

Thank you


Thank you very much for your attention.

I’ve downloaded the Configuration Tool through the informed link. It’s the same software I’m already using (version

But the problem is that the module still can’t link physically with my Ethernet network. With the Ethernet cable plugged in the RJ45 port, there are no signs of LAN activity (the RJ45 port LEDs do not blink, and the LAN switch in which the module is connected does not indicate a connection in the corresponding port).

In the module board, it’s written “WIZ108SR R1 4”. Is this the H/W version that you are asking? If not, where can I find this information?

We are a Brazilian company, and we have a employee who goes often to the USA. The modules were bought at the American Online Shop ( They were delivered in an USA address that the employee was staying, and then he got back to Brazil bringing the modules.

Yes, I am aware that they are 3.3V powered. I am using a nominal 3.3V power source. After reading your reply, I decided to measure the “real” output of my power source with a voltage meter, and I found out that its output is actually 3.7V!
This diference in voltage can damage the board, or cause it to not work properly?

Fillipe Couto


WIZ108SR updated version is H/W 1.4 and S/W

And strange measure 3.7V…

Please detail description. (below list)

  1. How to power supply?
  2. Where did you measure 3.7V ?
  3. Test configuration.

Please give me test configuration picture and diagram.

There is two LED in wiz108sr RJ-45.

Green is LINK LED , orange is ACT LED.

If it do not working, it was not connection. To network physical layer

And there are big possibility of problem in H/W.

Thank you


Thank you for your support.
I have realized just now what I was doing wrong.

I was not connecting the PIN 4 (nRESET) to 3,3 V after powering up de module.
In the user manual, it is written than this PIN is Active in LOW, so I though that I could just leave this pin floating (like selecting RS-485 in pin 10 - 485_SEL)

Upon connecting the pin 4 to HIGH (3,3 V), it started to work as expected.
My mistake! :slight_smile:

Once again, thank you very much for your attention.

Fillipe Couto