[Tagging] Telephone exchange

[Andy Townsend]

Re "central office", it's not really an English term.  I'm guessing that 
it was translated from French - see 
https://lists.openstreetmap.org/pipermail/tagging/2018-June/037016.html 
and 
https://wiki.openstreetmap.org/wiki/Proposed_features/Telecom_local_loop 
.  The English term that matches this concept is "Telephone Exchange".  
"amenity=telephone_exchange" is of course in common use, and if a 
building looks like a telephone exchange (certainly many in the UK have 
a common design) then "building=telephone_exchange" may also make sense.

"building=central_office" won't mean much to data consumers beyond 
"building=yes", but like Chris said, people can use whatever tags they like.

Best Regards,

Andy