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T-Mobile and Sprint’s new unlimited plans aren’t exactly unlimited
T-Mobile's CEO John Legere
T-MOBILE CEO JOHN LEGERE

Sprint and T-Mobile want to sell you unlimited data for less. But don’t start celebrating just yet.

Getting more data at a lower price should be good. But wireless broadband differs from wired broadband in one key way: scarcity. It’s hard to provide reliable wireless service if everyone is maxing out their connections at once.

That’s why Sprint (S) and T-Mobile (TMUS) each have to take a chisel to their definitions of “unlimited.”

What you lose at T-Mobile: tethering, HD video

The chisel in T-Mobile’s hands is arguably bigger than Sprint’s, though. To replace the company’s $95 unlimited plan with its new $70 per month “T-Mobile One” unlimited deal, which starts Sept. 6, T-Mo had to shackle tethering — the ability to share your phone’s connection with a nearby computer via WiFi.

Instead of the free but data-capped tethering that T-Mobile has provided since it debuted no-contract plans in 2013, T-Mobile One only allows unlimited tethering via its “2G” service, which offers speeds of no more than 236 kilobits per second.

To test that, I set my Android phone to connect to T-Mobile via 2G, tethered my laptop and tried to load Yahoo Finance’s home page. Four and a half minutes later, my MacBook Air’s Chrome browser gave up after loading just seven stories, two thumbnail pictures, some stock quotes and a logo or two.

Faster LTE tethering will cost $15 a month extra for a 5 GB allotment, about a third of the current unlimited plan’s 14 GB tethering allowance.

T-Mobile One also excludes streaming high-definition video from its new plan, instead limiting streaming video to standard definition. This “BingeOn” tradeoff is the default in current plans, and many users must not mind: Only .8% of subscribers opt out of it, T-Mobile Chief Technical Officer Neville Ray said in a conference call Thursday.

But if you do notice the difference, regaining HD streaming will cost $25 a month extra instead of being free.

All this makes “T-Mobile One” look more like “T-Mobile Asterisk.”

The carrier’s “T-Mobile Goes All In on Unlimited” blog post, which features a video of CEO John Legere declaring “the era of the data plan is over,” also implied T-Mo’s current plans will vanish for new customers.

Not so. Half an hour into a call with the press explaining the new plan, Legere clarified that “we’re not going to eliminate our other plans now.” T-Mobile PR confirmed Friday morning that the company’s current $50 per moth 2 GB, $65 per month 6 GB and $80 per month 10 GB plans will remain, as will their tethering allocations, T-Mobile’s Data Stash data rollover service and free BingeOn opt-out.