A consumer rights activist who led the charge against restrictions on phone unlocking has graded the four major US carriers and found three of them aren't fully complying with commitments they made to the government.

The CTIA Wireless Association promised the Federal Communications Commission that carriers would meet six conditions by a deadline that passed last week. But Sprint hasn't met three of the conditions, T-Mobile fails on two of them and possibly a third, while AT&T meets five but possibly not the sixth, reports Sina Khanifar, who was credited by the White House for starting the petition that helped (temporarily) legalize phone unlocking.

In addition to that legislation, carriers promised the FCC to post clear and concise unlocking policies on their websites, implement postpaid unlocking policies, implement prepaid unlocking policies, provide notice to customers when their devices are eligible for unlocking, respond to unlock requests within two business days, and unlock devices for deployed military personnel.

Khanifar analyzed the carriers' performance in living up to these conditions and summarized his findings in this chart:

Verizon has to follow a more strict policy on handset unlocking than its rivals because of conditions placed upon spectrum it bought at auction. "Verizon has the most lenient policy: they've almost entirely stopped locking their devices," Khanifar wrote.

Sprint fares the worst in Khanifar's analysis. In addition to not meeting three of the six requirements, the company also gives customers trouble in connecting devices from other carriers. The "Consumer Code" carriers signed up for does not include "a commitment from carriers to accept unlocked devices on their networks," leading to varying policies, Khanifar wrote.

"Interoperability is an obvious and critical piece of what makes unlocking valuable. If you unlock your phone, you need to be able to take it to another carrier and use it," he wrote. "But many carriers, most notably Sprint, specifically say that they won't activate phones that were originally sold by another carrier. That's despite the cellular technologies the phones use being entirely standardized. In Sprint's case, those restrictions even apply to their own MVNOs. Virgin Mobile devices run entirely on Sprint's network. But even if Virgin Mobile unlocks it for you, Sprint won't activate it for use on a prepaid or postpaid account. It's patently absurd: there's simply no good reason to prevent users from bringing their own devices—in fact, it makes it even hard for consumers to switch to your carrier. The only justification for that kind of policy is to gouge customers and force them to buy more expensive, 'carrier-approved' devices that come with 2 year contracts."

Sprint's policy says it "will only activate devices certified to work on the Sprint network and may not activate unlocked devices from other carriers/service providers, including devices manufactured for Boost Mobile, Virgin Mobile, and Assurance Wireless."

Even though Verizon met all six conditions, it isn't the friendliest carrier in terms of attaching other devices to its network, Khanifar wrote. "Their Bring Your Own Device" program makes it clear that your phone needs to be an 'unused Verizon phone' to be eligible," he wrote.

This appears to apply only to prepaid Verizon service. We asked Verizon if Khanifar's analysis is correct, and if so, how the carrier can prevent certain devices from connecting to its network without violating its spectrum requirements. We'll post an update if we get a response.

UPDATE: Verizon says it will connect non-Verizon devices for prepaid customers, and that the terms posted on its site are not written clearly enough. "That site was geared towards Verizon customers who can relate to having a phone they aren’t using or are off contract and want to move to prepaid," the company said. "To clarify though, you can bring your own device to prepaid and it can be a non Verizon device. The device does need to be compatible with our network and support the proper radio frequencies/bands in order to connect and it does need to be certified to work on our network."

The interoperability problem could be solved by the FCC's net neutrality proposal, which would prevent carriers from blocking non-harmful devices. Khanifar did not find any problems with AT&T's and T-Mobile's bring-your-own-device policies.

More on where the carriers fall short

Back to the six carrier commitments, Khanifar provided details on how he determined whether carriers met each one. Sprint's unlocking policy "can't be described as 'clear, concise and accessible,'" he wrote. The policy for prepaid devices "is hidden two links away at this URL."

Further, "Sprint says that they will only perform an 'International SIM unlock' for active customers," he wrote. "There appears to be no provision for unlocking phones for international use if you are not an active Sprint customer, which is one of the requirements of the CTIA’s 'Consumer Code.' Furthermore, they place restrictions on the number of devices you can unlock: for example, consumers don’t qualify for an 'international' unlock if they’ve unlocked a different phone in the past 12 months." The consumer code requires carriers to unlock devices for both current and former customers.

Sprint's military personnel policy is bad, too, Khanifar wrote. "Specifically, it refuses phone unlocking for any personnel who has 'previously unlocked another device within the past 12 months,'" he wrote. "That's well outside the voluntary guidelines of CTIA’s Consumer Code. What happens if a user’s phone or tablet is damaged or breaks while deployed?"

We asked Sprint for a response to Khanifar's analysis and will provide further details if we get them.

T-Mobile failed Khanifar's analysis with restrictions on its postpaid and prepaid policies. For postpaid, T-Mobile "prevent[s] consumers from unlocking more than 2 devices per line of service in a 12 month period. They also require devices on their monthly plans to have been active for at least 40 days, even if the contract expires after a month under T-Mobile’s Un-carrier policies and all dues have been paid." On prepaid, T-Mobile says, "The account must not be canceled and in good standing."

As for the required notifications, Khanifar wrote that "T-Mobile doesn’t indicate whether they’ll notify prepaid or postpaid customers of their unlock eligibility."

UPDATE: T-Mobile told Ars that it is complying with all of the commitments. "We are in compliance and worked with the FCC on the voluntary agreement and making sure our policy was in compliance," a spokesperson told Ars. “As the Un-carrier, we believe in more flexibility and transparency for our customers and want them to have freedom to bring their own device to the carrier of their choice. We worked hard to get an industry agreement on unlocking and our unlocking policy met with the CTIA requirements in advance of the deadline. In fact, T-Mobile has gone beyond the voluntary requirements and long been a champion of the 'Bring Your Own Device' concept for several years now."

T-Mobile did not address Khanifar's points about the 2-device limit and the prepaid restrictions. But the company told Ars that it does provide notifications. "We implemented the solution in late January. Customers who have devices that become eligible for unlocking will receive a line item notice on their bill letting them know," a T-Mobile spokesperson said.

UPDATE 2: T-Mobile has now addressed Khanifar's other complaints. On whether it will unlock devices for former pre-paid customers, the company said, “If a former T-Mobile customer calls to have an eligible device unlocked we absolutely work with them to provide a solution.” On the two-device limit, T-Mobile said, “An average consumer is typically not buying 3 or more phones every year, paying them off in full and unlocking them—it’s just not a consumer behavior that we see. So this requirement helps with fraud prevention and helps make sure our customers will be able to have access to our best device pricing deals. And it is in line with the CTIA requirements.”

The CTIA Consumer Code does not include any device limits.

AT&T met five of the six requirements, but it isn't clear whether it provides eligibility notifications to prepaid customers. "We were unable to find any information about whether AT&T has implemented any notification system to let prepaid customers know of their unlocking eligibility," Khanifar wrote. "We spoke to two customer service representatives who gave me conflicting accounts of how notifications might be delivered, and the official unlocking website was unclear."

We asked AT&T for a response to Khanifar's analysis and will provide further details if we get them.

UPDATE: AT&T's response is as follows: "AT&T is in compliance with the unlocking standards in the Mobile Wireless Device Unlocking Voluntary Commitment announced by the CTIA, including providing prepaid customers notice of when their devices are eligible for unlocking. The notification commitment for prepaid customers states that 'Notice to prepaid customers may occur at point of sale, at the time of eligibility, or through a clear and concise statement of the policy on the carrier’s website.' AT&T implemented the latter of these options, and notification may be found here."

AT&T has a history of being inflexible in unlocking phones, as Ars Senior Reviews Editor Lee Hutchinson can confirm. We also just heard from an AT&T customer who says it took three months to get a phone unlocked.

While the big four carriers and a few others committed to follow the CTIA code, TracFone did not.

"TracFone has a ridiculously abysmal unlocking policy," Khanifar told Ars. "It amounts to: 'Maybe, someday, we'll allow you to unlock your phone.' It's a great example of the weakness of the 'voluntary agreement' approach the FCC took with this."

Still seeking a permanent solution

Khanifar also wants Congress to reform the Digital Millennium Copyright Act (DMCA), which has caused problems for customers seeking to unlock devices.

"Unfortunately a shortsighted and clumsy provision of the Digital Millennium Copyright Act can make it completely illegal for consumers to modify the devices, software and content they purchase," he wrote.

President Obama signed a bill providing a temporary exemption for phones, but not tablets. The DMCA gives the Librarian of Congress power to grant or deny exemptions, and the Librarian could once again deem phone unlocking illegal later this year.

"There's a simple and easy fix to all this," Khanifar wrote. "Congress could pass a bill clearly stating that it's not illegal to circumvent a lock as long as there's no intention of copyright infringement."