Section 255 of the Telecommunications Act, which took effect in 1996, requires that telephone products and services be accessible to people with disabilities to the extent access is "readily achievable." The American Foundation for the Blind has a web page for consumers, Cell Phones, Tablets, and Other Mobile Technology for Users with Visual Impairments.
The web page includes information on the right to have your phone bill and phone manual in an accessible format, features to look for when purchasing a phone, and information on whom to contact for an explanation of the accessibility features available and what to do if you have problems obtaining accessible phones or services.