Canbus on Siemens S5 155U

Our customer has a S5 155 that has a Canbus card in the central rack.
I only have a picture here, and cannot see the device number.
I don't see a manufacturer name on the card, so I suppose it is an original Siemens card.
Does anyone know of the existance of such a card, and can give me a reference, so I can search for a manual.

I am not 100% sure, but I think maybe INAT made this card.
INAT has been taken over by Softing, and their old S5 products can no longer be found.

It is horrible to have such a projekt consisting of an obsolete S5 PLC with a 3rd party module that is also obsolete and for which no support can be found.
Seriously, consider to replace ALL of the old system for something newer and uptodate.

I found the Manufacturer, its ESD from Germany.