@stahlmann Yes!
Mostly telecom=service_point (DSLAM/MSAN or OPT for optical) and telecom=exchange (HvT). I've put some more links to #osmwiki and some background info here:
https://todon.eu/@ljrk/114382830197212951
Within Berlin, we have only 3 "grey cabinets" tagged as connection_point (Kabelverzweiger, passive devices) and 89 as service_device (active devices that don't do distribution frames) as well as around 100 exchange's. The exchange tags are probably complete, but every exchange bundles a *lot* of connection_point's, or, with the increasing amount of outdoor DSLAMs, service_device's.
With FTTB/FTTH the DSLAM is either moved into the building (Micro DSLAM) or DSL is foregone completely, thus reducing the need to tag these, but KVz's still persist (as purely passive distribution points, now routing fiber rather than copper).
Also, most KVz are not tagged to specify the medium (fiber/copper) they are connected with, DSLAMs should probably always be tagged as fiber.
But not all "grey cabinets" are telecommunication infra, some are used for other devices. You can query them using https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dstreet_cabinet.