@D-C @Clive_A Thank U guys. Most appreciated.

@Clive_A so, if I understand you correctly, even though the fiber switch and the individual components can transmit at 10G, they will not transmit at 2,5G, if the fiber switch is linked by a 2,5G...

Hi, guys. Hardware: All TP-link gear. Router ER7412-M2 v1.0, factory reset, no VLANs. 1.0.1 Build 20240719 Rel.56423 - the newest. Switch has newest firmware, fiber switch. Router and switch...

@D-C I double checked everything, and I have somehow managed to get the multi-mode SFPs. You were too fast, I can't delete the thread. :-)

SX3008F fiberswitch, receiving signals from ER7412-M2 v1.0 2.5gig port via SFP ethernet adapter, ports working nicely with 1000Mbps SFP modules. Bought the new MC420L media converter, SM5110-SR...