Section 255 of the Telecommunications Act, which took effect in 1996, requires telecommunications products and services to be accessible to people with disabilities to the extent access is "readily achievable," meaning easily accomplishable, without much difficulty or expense. If manufacturers cannot make their products accessible, then they must design them to be compatible with adaptive equipment used by people with disabilities, where readily achievable. Examples of products Section 255 covers include telephones, pagers, fax machines, modems, and telephone company switching equipment. The Federal Communications Commission (FCC) enforces Section 255.
More information about Section 255 can be found at the Access Board's web pages, Section 255: The Law and About the Telecommunications Act Section 255 Guidelines, and the FCC's Section 255 Telecommunications Access for People with Disabilities.