In the US, Nextel called it 'DirectTalk' and included it as a free service on most new models of Motorola handsets.
Boost Mobile disabled the function via handset software settings.
SouthernLINC calls it LINCaround and ships handsets with the feature disabled.
It can be used for voice communication, as well as SMS (short message services) between devices over more than 8 miles in flat terrain conditions.
The effective range can be in excess of 8 miles in flat terrain, but the frequencies used are line-of-sight and are blocked by structures and vegetation.
The MOTO Talk service is slightly similar to FRS (Family Radio Service) walkie-talkies but uses digital rather than analog signals, operates on the 900 MHz ISM band rather than the 462 MHz frequencies allocated to FRS, and uses frequency-hopping spread spectrum technology rather than single fixed frequencies for each channel.
Boost Mobile phones are not enabled for MOTO Talk use by default but can enabled by modifying the codeplug of the device (The Motorola i415 has the codeplug entry but not the needed transceiver hardware.
They use similar commercial radio transmission systems for DTR Digital series businesses but they are not compatible with each other, because they are configured differently by software.
The signals can not be interfered in a conventional manner (blocking the TX / RX frequency).