We go to every emergency incident with the anticipation that we will encounter people with special needs. TDD and TTY are interchangeable terms for technology called the Telecommunications Device for the Deaf. The system consists of a typewriter-like device that plugs into the regular phone system. The device includes a keyboard and display so that it can send or receive typed messages. The system can be bought commercially, usually running in the hundreds of dollars.
Some states provide the technology to qualifying individuals free or for a nominal charge.
FEMA recommends keeping an accessible phone and a whistle by your bed along with a list of emergency numbers and your eyeglasses. It's a good idea to have an accessible phone in each room of the house, too, and to consider purchasing a cordless phone. Get a programmable phone. You may want to look into commercial services that let you call for help at the touch of a button on a remote device, such as one worn around the neck. Phoenix offers such a system to people with special needs at no charge.