OTTAWA - Cellphone companies will soon no longer be allowed to charge customers to unlock their devices under sweeping changes to Canada's wireless code of conduct announced today.

The new code from the Canadian Radio-television and Telecommunications Commission also says all newly purchased devices must be unlocked, beginning Dec. 1.

The telecom regulator is making several other changes to the code that it says will give Canadians more control over their wireless services.

The updated code, which originally came into effect in 2013, now stipulates:

- Unsatisfied customers will be able to cancel contracts within 15 days, as long as the returned devices are in near-new condition and they haven't used more than half of their monthly usage.

- Only the wireless account holder on family or shared plans can consent to overage and roaming charges, unless others on the plan are expressly authorized to approve the costs.

- Data caps will also be tied to single accounts, no matter how many devices are listed on a shared plan.

- Wireless service providers cannot unilaterally change the key terms of a contract with a customer for voice, text or data services.

The changes come six months after the regulator heard from consumer groups, who said some cellphone companies were violating the code, either passively or actively, and called for the rules to be tightened and enforced.

“The changes and clarifications we are announcing today will give Canadians additional tools to make informed choices about their wireless services and take advantage of competitive offers in the marketplace,” CRTC chairman Jean-Pierre Blais said in a statement.

“While they appreciate the code, (Canadians) told us loudly and clearly that it could be more effective. We have listened to them,” said Blais, who will end his term at the helm of the regulatory body this week.