BEIJING, Sept. 4 (Xinhuanet) -- America's largest wireless carrier, AT&T Inc., will launch a service Tuesday that promises to be a teen's worst nightmare: parental control of mobile phones on almost all of its 63.7 million subscriber lines.

That means limits on when a wireless phone can receive and make phone calls and to whom, set allowances for ring tones and other downloads, and restrictions on text messages and talk time.

"We were certainly hearing from parents who were dismayed at overuse of text or phones," said Carlton Hill, vice president of voice products for AT&T's wireless unit and the mother of two teenagers. "We want to find a way for kids to use phones without having to take the phone away."

Many parents want their children to have a mobile phone for safety reasons, but don't want them making or receiving non-emergency calls during the school day, chatting away all the shared family-plan minutes or running up the phone bill with text messaging charges, Hill explained.

AT&T's Smart Limits service will be offered as an add-on for 4.99 U.S. dollars a month per line. No contract will be required, and it will work on all but a handful of customer lines left on an old network the company is phasing out.

The functions, ranging from call blocking and hour limits to text message and download allowances, will be set through a website. Calls to or from a parent's number can be made to override the restrictions, and calls to 911 can be made anytime.

The AT&T service also allows filtering of websites parents don't want their children accessing from their phones, but that function will not work on Apple Inc.'s iPhone because of the browser, said AT&T spokesman Fletcher Cook.

The website filter will also be inoperable when a phone is using a Wi-Fi network because AT&T can only block content delivered over its wireless networks.

(Agencies)