Hundreds of Americans have left comments for the Federal Communications Commission to tell the board mobile broadband should not be considered a full replacement for high speed internet service at home.

The response came after the FCC launched its annual study of broadband deployment and suggested access to a smartphone and mobile broadband networks could be considered a suitable substitute for cable or fiber internet.

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More than 300 comments have been filed by Americans who object to the notion that mobile broadband can serve as a replacement to a high-speed connection at home, citing a number of limitations imposed by mobile carriers that make the service less capable of serving the needs of the average broadband user.

First and foremost is the considerable gap in data speeds. The standard for mobile broadband are speeds of 10 Megabits per second (Mbps) for downloads and 1Mbps for uploads. A recent survey from OpenSignal found T-Mobile had the fastest network on average, with a download rate of 16Mbps, while Sprint was the only major carrier to fail to break the 10Mbps threshold.

In the case of most mobile carriers, the average download speed is half of what is required to qualify as broadband for a home network. By the FCC’s definition, a broadband connection requires 25Mpbs download speeds and 3Mpbs upload speeds—a bar not even the fastest mobile network in the U.S. reaches.

On top of the slower speeds, many mobile connections are limited by restrictions imposed by the carrier. Most mobile network providers implement data caps, meaning users only have a limited amount of online access before they are charged more or have their connection throttled.

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Home internet connections are not necessarily without data caps, but they are considerably higher. Caps put in place by broadband providers have typically allowed for at least 300GB of data per month, compared to caps of between 2-10GB for most mobile plans.

It is not uncommon for mobile networks to have other restrictions as well, including limits on tethering that would allow a person to access the internet from another device by using a smartphone as a hotspot. Such a feature would seem to be necessary if one wanted to replace home broadband with a mobile alternative.

Despite the considerable limitations posed by the current state of mobile connections, FCC Chairman Ajit Pai—who was appointed to the position by President Donald Trump—may conclude that access provided by mobile network is good enough for large chunks of the country that currently have limited broadband access.

Such a conclusion would mark a considerable departure from the position of the FCC under former Chairman Tom Wheeler during the Obama administration. Prior to stepping down from the role, Wheeler said Americans should have access to fast internet connections both at home and from mobile networks.

The FCC is accepting comments on it proposal through September 7, with a period for reply comments open until Sept. 22.