While looking into a board I found a little transformer. At the beginning I thought it was a high frequency transformer, but then I realized it was like 4 individual inductors. I attach a diagram of what I saw. The VCC, GND, TX and RX signals were passed through inductors to go somewhere else. I wish I could attach a picture of the array, but actually it looks like a little high frequency transformer very similar to one attached. I have two same boards with those transformers, but they have different marking codes, one says C12B4 and the other C1001311, so it's been impossible for me to find the real part number so that I can buy it. Do you know how I can identify this component or something similar available to purchase in some online supplier?

 

Looks like it is a common mode choke used to reduce interference.
http://www.we-online.com/web/en/pas...m/blog_detail_electronics_in_action_61439.php

 

Looks like it is a common mode choke used to reduce interference.
http://www.we-online.com/web/en/pas...m/blog_detail_electronics_in_action_61439.php

Never seen one like that - but what you said feels right.

 

Looks like it is a common mode choke used to reduce interference.
http://www.we-online.com/web/en/pas...m/blog_detail_electronics_in_action_61439.php

Many logic boards have such filters to reduce the interference to everything off the board. And some have the same kind of filter to keep interference out of the board. AND, some brilliant? people have even used exactly the same parts as actual transformers. It is very fortunate that the connections are marked, it will make using or checking the board a bit simpler.

 

Looks like it is a common mode choke used to reduce interference.
http://www.we-online.com/web/en/pas...m/blog_detail_electronics_in_action_61439.php

I also think so. But I do not like such things, where I am guessing in nothing. At least attach the part number of the device, so we can check what might be inside.