The fight over using smartphones to make Wi-Fi-enabled telephone calls just entered the unexpected area of disability rights. AT&T has accused rival carriers T-Mobile and Sprint of violating rules set by the Federal Communications Commission (FCC), which require wireless services to accommodate users with speech and hearing disabilities. Unlike AT&T, both T-Mobile and Sprint allow users to make calls on iPhones over Wi-Fi.

TTY devices, which are used by the deaf and hearing-impaired to operate telephones, allow them to type messages rather than listening and speaking. But those devices don’t necessarily work reliably over wireless networks, even though the FCC has mandated that TTY devices should be able to make 911 calls over Wi-Fi.

In a letter to the FCC, AT&T flagged the supposed violation by T-Mobile and Sprint, but claims it does not want to stop its competitors from offering Wi-Fi calling functionality; instead, the company is requesting a waiver so it can provide the same service, but with clearance from the FCC.

Using Wi-Fi instead of 4G or 3G networks to make telephone calls is increasingly being favored by budget-conscious users: It does not use minutes, and essentially allows you to make calls for free. However, AT&T declined to issue the feature for the new iPhone in September, allegedly because it was waiting for FCC approval.

It seems AT&T is regretting its decision to fully comply with government regulations designed to protect the disabled; its hands are tied until the FCC grants a waiver. Users with speech and hearing disabilities now have a plethora of options for communicating reliably via iPhones, including multiple ways to contact 911.

[via Ars Technica]