The United States Federal Communications Commission yesterday sent letters to T-Mobile, AT&T, and Comcast questioning the companies about mobile services that allow customers to access certain content without paying for the data usage, reports Bloomberg. While the FCC has been careful to note the inquiry is "not an investigation" and designed to help the FCC "stay informed as to what the practices are," there have been some questions about whether such services violate net neutrality rules.

Under scrutiny is T-Mobile's Binge On program, which allows customers to stream 480p video that doesn't count against a data cap, AT&T's Sponsored Data program that lets AT&T customers view sponsored content for free, and Comcast's Stream TV, a video service that does not count against data caps in areas where data caps are imposed. Ars Technica has uploaded a copy of the letters that were sent to the three companies.



Back in February, the FCC voted in favor of new net neutrality rules preventing Internet providers from blocking or throttling web traffic or offering prioritized service for payment, but it has not specifically addressed these "zero-rating" data exemption programs. Last month, FCC chairman Tom Wheeler said the organization would keep an eye on T-Mobile's Binge On service, but praised it as being both "highly innovative and highly competitive."

In a statement, a T-Mobile spokesperson said the company is "looking forward" to talking with the FCC, and believes Binge On is "absolutely in line with net-neutrality rules." Comcast expressed a similar sentiment, stating it looks forward "to participating in the FCC's fact-gathering process relating to industry practices." An AT&T spokesperson said AT&T is committed to "innovation without permission" and expressed hope the FCC is too.

The FCC has requested "relevant technical and business" representatives from T-Mobile, AT&T, and Comcast be made available for discussions by January 15.