• AT&T is a telecommunications corporation.

AT&T is a telecommunications corporation. (Photo : Reuters )

AT&T accused Sprint and T-Mobile on October 2, Friday of violating the United States' federal rules requiring wireless networks to be compatible for tech for people with hearing and speech disabilities. The Dallas-based company argued in a letter to the Federal Communications Commission (FCC) that the two rival carriers were in "defiance" by offering Wi-Fi calling on mobile phones without securing a waiver from the FCC for teletypewriters (TTY). Deaf and speech-impaired people use TTY with smartphones to transmit cell phone calls, such as for 911 emergencies.         

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TTY devices operate poorly over wireless Wi-Fi. However, AT&T complained to FCC Chairman Tom Wheeler that Sprint and T-Mobile have been offering Wi-Fi calling services for quite a while. That has been over a year for Android phones, and months for iOS devices. AT&T asserted this was an FCC violation.

The telecommunications company requested a temporary waiver of the Commission's rules in July so it could offer Wi-Fi calling in September, according to Pulse Headlines. It hopes to replace TTY with real-time text (RTT). The telecom has requested that the FCC adjust its rules to permit RTT as a substitute for TTY, but hopes to offer the latter until the Commission green lights its request.

AT&T argued that it has been unable to offer TTY service without an FCC waiver, although rival nationwide carriers are doing as such without one. They are "in defiance" of FCC rules.                

T-Mobile told Ars Technica that it supports TTY and is complying fully with FCC rules. However, neither company has admitted that it supports TTY devices through Wi-Fi calling.

FCC spokesman Mark Wigfield has stated that telecoms such as wireless and Voice over IP (VoIP) must make their services available to people with disabilities, including via TTY. It is also reviewing AT&T's waiver request for TTY devices, according to Ars Technica.      

AT&T wrote to the FCC that disability advocates want RTT access as soon as possible. However, they do not oppose a short-term waiver of current TTY rules.

A deaf physicist named Robert Weitbrecht developed TTY in the 1960s. The 1973 Manual Communications Module (MCM) was the world's first two-way electronic portable TTY.