FEDEVEL
Platform forum

Sniper2 , 07-25-2024, 04:14 AM

So I have a incoming base100 ethernet port and a base1000 phy on my pcb .
I have 2 rx and 2 to pairs and I assume it matters what pairs I connect to the base100 connector.
I assume it is the first pair of each.
Am I correct?
Also regarding the unused pairs is it OK to leave them floating? Or should I terminate them with 100ohm ?

Sniper2 , 07-26-2024, 01:15 PM

Yes I should terminate

Robert Feranec , 07-26-2024, 02:12 PM

I believe 1000BASE should be able to recognize it is talking to 100BASE ... I don't remember doing any special termination. BTW, this is an interesting website, can help: https://www.practicalnetworking.net/stand-alone/ethernet-wiring/

Sniper2 , 07-26-2024, 05:55 PM

well it is like this:
Gb switch is on my PC and i have 100base ethernet on a non RJ45 conector and basicaly i need to leave the 2 not used pairs floating or terminate with proably 100 ohm

Sniper2 , 07-26-2024, 06:00 PM

PS i also have a SGMII unused do i need to terminate that somehow?

QDrives , 07-26-2024, 08:17 PM

Why have a 1Gbps phy if you can only do 100Mbps? Doesn't that make things more complicated?

Sniper2 , 07-26-2024, 08:53 PM

switch*

Sniper2 , 07-26-2024, 08:54 PM

some ports need to be GB and a few can only do 100base

QDrives , 07-27-2024, 07:36 PM

But is your connection / connector able to do so? Is your "non RJ45 connector" able to handle Gb?

Sniper2 , 07-27-2024, 08:53 PM

yes

Sniper2 , 07-27-2024, 08:53 PM

base100ethernet is no so picky

QDrives , 07-27-2024, 09:37 PM

If your device has Gb PHY and connector, you do the layout as if Gb.
If you connect only a 100Mb cable, that does not make a difference.
https://dgonzalez.net/papers/roc/stdwiring.png

Sniper2 , 07-27-2024, 09:46 PM

yes i did that