2.5G SFP module is also known as OC-48 or STM-16. The transmission speeds is up to 2488.32 Mbit/s.
For more knowledge about SONET/SDH data rates: https://community.fs.com/blog/how-much- ... odule.html

Maybe this is the reason why this 10GBASE-T copper SFP+ transceiver is cheaper than many other vendors. I search on the Internet, prices vary enormously from vendor to vendor. For example: https://www.fs.com/products/66612.html US$ 280.00 https://www.startech.com/Networking-IO/sfp/modules/10gbase-t-...

"This SFP module is design for 10KM but the run is in a building and probably less than 100m I don’t see a single mode 10Gbps SFP module designed for shorter distances." The transmission distance is less than 100m, then why not use LRM SFP+ module that support 220m? Or you can take the ad...

SFP+ DACs compatiblity is a troubling issue, that I met many times. Luckily, I used to get MikroTik SFP+ DAC 3m for my server connections, no issues. But now I have replaced those DACs with some new SFP+ DACs from other sllers, they works fine too. Maybe you can have a try.