Abstract: An officer can utilize an offender monitor to track remotely and manage the whereabouts of an offender, such as someone who as been convicted of a crime and is on parole. The officer can compose and send custom messages to send to the offender via the offender monitor. The offender monitor can store a received message so that the offender can play the message at an appropriate time via pressing a button on the offender monitor or making another input. If the officer deems that a message is urgent or needs to be played immediately, the officer can transmit a command to the offender monitor that causes the message to be played automatically.

Abstract: A portable device, for example an offender monitor, can utilize a GPS receiver or other location detector to provide locational information for the device. The portable device can communicate over a cellular network, for example using a radio to transmit location readings over the network. The location detector and the radio can draw power from an onboard battery. The portable device can operate in at least two modes. When charge of the battery drops below a threshold, the device can switch from the first mode of operation to the second mode to conserve power and avoid fully depleting the battery.

Abstract: A portable device, for example an offender monitor, can utilize a GPS receiver or other location detector to provide locational information for the device. The portable device can communicate over a cellular network, for example using a radio to transmit location readings over the network. The location detector and the radio can draw power from an onboard battery. The portable device can operate in at least two modes. When charge of the battery drops below a threshold, the device can switch from the first mode of operation to the second mode to conserve power and avoid fully depleting the battery.