I actually rented a TTY in my office for a long time and stopped doing it, because the deaf community has moved so quickly to the Internet and to short messaging and such that we just weren't getting any action on it. However, it's interesting that the augmented phones for the hard of hearing are useful; for the deaf, they're less so.
Pendant longtemps, j'ai loué un ATS pour mon bureau, mais j'ai cessé de le faire parce qu'avec l'arrivée de l'Internet et des services de messages courts, les personnes sourdes ont rapidement cessé de l'utiliser.