Speaking about 911,
I recommend to keep the TTY as for backup to call 911 because I believe it faster contact than VRS.
But I use more often to call VRS than hardly rare to use TTY.
Reason TTY is quicker to dial 911 and back off then leave it “on” ……..that it.
Firetruck or Police do come fast.
That VRS is take longer to wait available to get it.
which one go for it to save “Life” …… know what i mean. big issuse about it.

my concern about TTY machine seem may fade away years later. where is backup!

Thank You
Davy