Ethernet Recommendation (J1B1211CCD Out of Stock)

[airpanther]

Good day,

Our latest project requires ethernet, and we would like to add the J1B1211CCD directly to the board, but it appears DigiKey and Mouser are out of stock. However, there are nearly 10,000 RB1-125BAG1A units in stock. I'd like to go with the J1B1, but fear availability may be a problem for a while.

Below is how I am wiring the RB1-125BAG1A. However, I can't find an equivalent to Pin 8, which is grounded on the J1B1211CCD (see PJRC Diagram below). On the spec sheet, the internal resistors appear to be grounded to the shield, but I can't figure out which pin exposes that ground and if it needs to be attached to the Ground on the Teensy.

Also, in general, is this the right way to wire the RB1-125BAG1A, with all the other pins straight to the Teensy 4.1 Ethernet pins? Is





Thanks,
Robert

[PaulStoffregen]

RB1-125BAG1A was confirmed working with this earlier PCB design.

https://oshpark.com/shared_projects/5epewE3O

[airpanther]

Hi Paul,

Thank you very much for your reply! I did take a look at that, which was helpful. I think I found the answer... the Eagle library for the RB1-125BAG1A (from SnapEDA) is missing S1/S2, so I couldn't find a way to properly ground the jack. Since this is for a custom PCB, I will modify the library to properly include S1/S2.

Thanks again!
Robert

[PhilB]

Good day,

Our latest project requires ethernet, and we would like to add the J1B1211CCD directly to the board, but it appears DigiKey and Mouser are out of stock. However, there are nearly 10,000 RB1-125BAG1A units in stock. I'd like to go with the J1B1, but fear availability may be a problem for a while.

Below is how I am wiring the RB1-125BAG1A. However, I can't find an equivalent to Pin 8, which is grounded on the J1B1211CCD (see PJRC Diagram below). On the spec sheet, the internal resistors appear to be grounded to the shield, but I can't figure out which pin exposes that ground and if it needs to be attached to the Ground on the Teensy.

Also, in general, is this the right way to wire the RB1-125BAG1A, with all the other pins straight to the Teensy 4.1 Ethernet pins? Is





Thanks,
Robert

I use that MagJack in my grblHAL board. Actual circuit below. Works really well. There are quite a few boards in use with the MagJack installed. For what it is worth, I have tested the T4.1 with about 10 different MagJacks and they all work pretty well.

Also, if you are looking for volume, you can find the RB1-125BAG1A on AliExpress for a lot less than the mainstream distis (including LCSC). And, no they do not appear to be counterfeit and work quite well. Zero complaints with hundreds of RB1-125BAG1A shipped to end users.