theyre not old and still used in many many cell modems :-)

Yup.

Bluesky's name collision was pretty avoidable here but I guess they thought the obvious name was BS.

I believe that's still used in phones for communication between the computer and the cell phone hardware.

ATDT <My Favorite BBS>

. . .

ATH

Same. ATS11=43 was magic back in the day.