https://man.netbsd.org/ttys.5
ttys(5) - NetBSD Manual Pages
manual pagesttysnetbsd
https://wiki.wlug.org.nz/ttys%284%29.html
WlugWiki - ttys(4)
ttys
https://connectionsmagazine.com/article/ttys-in-call-centers-of-today/
TTYs in Today’s Call Center | Connections Magazine
Call centers are now being equipped with devices that allow the center to communicate with people who are hearing-impaired.
call centerttysconnectionsmagazine