This is the split system from Cidatech. I have encountered this again and again with customers.
It is possible because only 4 PINs are connected and the link with the MC220L is not working.
Ev. A specialist shop near you can convert this (crap) to a gigabit network.
There has been a lot of discussion here in the forum about these stupid split systems, just to save a few francs.
The customer thinks he has received new, modern cabling. New but not modern.
The GigaBit standard was introduced in 1999.
Greetings compa