Mo. Rev. Stat. § 209.260

Telecommunications companies shall ensure, if readily achievable as defined by federal law 42 U.S.C.A. section 12181(9), that high quality existing and new telecommunications services are available, accessible and usable by individuals with disabilities, unless making the services available, accessible or usable would result in an undue burden, including unreasonable costs or technical infeasibility, or would have an adverse competitive effect.