My Mom's deaf. I typically talk to her using a TTY service and she has a TTY phone at her house. I've looked in to iOS TTY and all it ever says is about connecting a cable to the iPhone to use a physical TTY. TTY uses 50bit per second baud-dot code for communications it should be trival to write a program that generates it on the iPhone. Just a sequence of tones, at a relatively low baud rate. BUT I need to be able to control the phone functionality from an app... Then I could type messages like "txting" and have it send baud dot code to my mom's phone. (I've tried giving her a computer, but she's 86... Old dog... new tricks...)
Any ideas?