In March 2006 NTT DoCoMo will launch a service that allows parents to regularly monitor the whereabouts of their children through their offspring's mobile phones, it said yesterday.

The service, called 'Imadoco' (Japanese for 'where are you now?'), allows parents to poll NTT DoCoMo to find out the location of their children's phone or receive regular emails from the network detailing its current location.

To coincide with the launch of the service the carrier, which is Japan's largest mobile phone operator, will also release a handset for children that includes features such as a panic alarm that kids can activate if they feel they are in danger. The SA800i phone has also been designed to prevent children from disabling the tracking function.

Imadoco requires the child to have a 3G mobile phone and the parent to have any 2G or 3G handset that supports the I-mode wireless data service. On most 3G handsets the location is calculated using information from nearby base stations although GPS-equipped handsets will offer a much greater level of accuracy.

Parents subscribed to the service will be able to request the location of the child's cell phone or set the network to automatically send updates on the location of the phone every 15, 30 or 60 minutes. Searches will also be possible from PCs.

On the SA800i when the alarm is activated a 100dB buzzer will sound and the handset will automatically call up to three pre-registered numbers with a voice message until each number picks up or until a passcode is entered into the handset. Parents with subscriptions to the Imadoco service will also get automatic email updates of the location of the phone every 15 minutes for nearly three hours.

The SA800i makes it difficult to disable the monitoring function. The battery is held in place with a screw that requires a special tool for removal and passcodes protect the network and phone settings menus. The phone can also be set so that it automatically switches itself on and sends location information should the child turn it off. Other child-friendly features include the ability to disable more complicated Chinese characters on the on-screen display and replace with easier to understand Japanese hiragana characters.

NTT DoCoMo hasn't yet set a price for the handset but anticipates it will cost about the same as current phones. The Imadoco service will carry a ¥210 (£1) monthly charge and a per-search charge of ¥5 (less than 1p).

The handset's introduction comes as news of attacks on children is increasingly common in Japan. While Japan has traditionally enjoyed an image as one of the safest societies in the world, the country has been rocked by a series of abductions, attacks and murders of children over the past few years.

The most recent came earlier this week when a 7-year girl was found dead in a cardboard box in Hiroshima in the west of Japan. She went missing as she returned home from elementary school at lunchtime and police suspect she was killed as she walked home, according to local media.

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