Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include memory and processor circuitry to execute computer readable instructions to at least measure with a first sensor, a first magnetic field in at least three dimensions, the first magnetic field including a device magnetic field caused by a wire attached to a device to supply electricity to the device, the first sensor proximately arranged to the wire, measure with a second sensor, a second magnetic field associated with an environment at least a first distance from the wire, and compare (a) the first magnetic field as measured by the first sensor arranged proximate to the wire and (b) the second magnetic field as measured by the second sensor.

Abstract: Example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to detect an operational state (such as an on/off state) of a media device are disclosed herein. Disclosed example apparatus are to monitor for activity on a first bus of an (HDMI) port of the media device. Disclosed example apparatus are also to inject a message with a first address on the first bus in response to detection of no activity on the first bus for at least a threshold duration. Disclosed example apparatus are further to detect the operational state of the media device based on whether a response to the message is received on the first bus.

Abstract: Example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to detect an operational state (such as an on/off state) of a media device are disclosed herein. Disclosed example apparatus are to monitor for activity on a first bus of an (HDMI) port of the media device. Disclosed example apparatus are also to inject a message with a first address on the first bus in response to detection of no activity on the first bus for at least a threshold duration. Disclosed example apparatus are further to detect the operational state of the media device based on whether a response to the message is received on the first bus.

Abstract: Example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to detect an operational state (such as an on/off state) of a media device are disclosed herein. Disclosed example apparatus include activity detection circuitry to monitor for activity on a first bus of an (HDMI) port of the media device. Disclosed example apparatus also include probe circuitry to inject a message with a first address on the first bus in response to detection of no activity on the first bus for at least a threshold duration. Disclosed example apparatus further include state detection circuitry to detect the operational state of the media device based on whether a response to the message is received on the first bus.

Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include memory and processor circuitry to execute computer readable instructions to at least measure with a first sensor, a first magnetic field in at least three dimensions, the first magnetic field including a device magnetic field caused by a wire attached to a device to supply electricity to the device, the first sensor proximately arranged to the wire, measure with a second sensor, a second magnetic field associated with an environment at least a first distance from the wire, and compare (a) the first magnetic field as measured by the first sensor arranged proximate to the wire and (b) the second magnetic field as measured by the second sensor.

Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include a first sensor to be positioned a first distance from a wire to measure a first magnetic field associated with the wire, and a second sensor to be positioned a second distance, greater than the first distance, from the wire to measure a second magnetic field, the second distance to reduce detectability of the first magnetic field by the second sensor. Disclosed example apparatus further include a comparator to compare the first magnetic field and the second magnetic field to determine an operational status of the device, and a meter to collect audience measurement data based at least in part on the operational status of the device.

Abstract: Example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to detect an operational state (such as an on/off state) of a media device are disclosed herein. Disclosed example apparatus include activity detection circuitry to monitor for activity on a first bus of an (HDMI) port of the media device. Disclosed example apparatus also include probe circuitry to inject a message with a first address on the first bus in response to detection of no activity on the first bus for at least a threshold duration. Disclosed example apparatus further include state detection circuitry to detect the operational state of the media device based on whether a response to the message is received on the first bus.

Abstract: Methods and apparatus to prevent unauthorized modem use are disclosed. An example apparatus includes a locking circuit; and a host authorizer to, when a received attention (AT) command pattern from a host device matches an AT command pattern, transmit a first voltage to the locking circuit to cause the locking circuit to enable modem functionality and, when the received AT command pattern does not match the AT command pattern, transmit a second voltage to the locking circuit to cause the locking circuit to disable modem functionality.

Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include a first sensor to be positioned a first distance from a wire to measure a first magnetic field associated with the wire, and a second sensor to be positioned a second distance, greater than the first distance, from the wire to measure a second magnetic field, the second distance to reduce detectability of the first magnetic field by the second sensor. Disclosed example apparatus further include a comparator to compare the first magnetic field and the second magnetic field to determine an operational status of the device, and a meter to collect audience measurement data based at least in part on the operational status of the device.

Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include a first sensor to be positioned a first distance from a wire to measure a first magnetic field associated with the wire, and a second sensor to be positioned a second distance, greater than the first distance, from the wire to measure a second magnetic field, the second distance to reduce detectability of the first magnetic field by the second sensor. Disclosed example apparatus further include a comparator to compare the first magnetic field and the second magnetic field to determine an operational status of the device, and a meter to collect audience measurement data based at least in part on the operational status of the device.

Abstract: Methods and apparatus to prevent unauthorized modem use are disclosed. An example apparatus includes a locking circuit; and a host authorizer to, when a received attention (AT) command pattern from a host device matches an AT command pattern, transmit a first voltage to the locking circuit to cause the locking circuit to enable modem functionality and, when the received AT command pattern does not match the AT command pattern, transmit a second voltage to the locking circuit to cause the locking circuit to disable modem functionality.

Abstract: Methods and apparatus to prevent unauthorized modem use are disclosed. An example apparatus includes a locking circuit; and a host authorizer to, when a received attention (AT) command pattern from a host device matches an AT command pattern, transmit a first voltage to the locking circuit to cause the locking circuit to enable modem functionality and, when the received AT command pattern does not match the AT command pattern, transmit a second voltage to the locking circuit to cause the locking circuit to disable modem functionality.

Abstract: Methods and apparatus to prevent unauthorized modem use are disclosed. An example apparatus includes a locking circuit; and a host authorizer to, when a received attention (AT) command pattern from a host device matches an AT command pattern, transmit a first voltage to the locking circuit to cause the locking circuit to enable modem functionality and, when the received AT command pattern does not match the AT command pattern, transmit a second voltage to the locking circuit to cause the locking circuit to disable modem functionality.

Abstract: Methods, apparatus, systems and tangible computer readable storage media are disclosed to determine an operational status of a device. Disclosed example apparatus include a first sensor to be positioned a first distance from a wire to measure a first magnetic field associated with the wire, and a second sensor to be positioned a second distance, greater than the first distance, from the wire to measure a second magnetic field, the second distance to reduce detectability of the first magnetic field by the second sensor. Disclosed example apparatus further include a comparator to compare the first magnetic field and the second magnetic field to determine an operational status of the device, and a meter to collect audience measurement data based at least in part on the operational status of the device.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed to determine an operational status of a device. An example method includes determining, with a processor, a first multi-dimensional measurement of a first magnetic field generated by a power cord to supply power to a device; and determining, via the processor, an operational status of the device based on the first multi-dimensional measurement.

Abstract: Methods, apparatus, systems and articles of manufacture are disclosed to determine an operational status of a device. An example method includes determining, with a processor, a first multi-dimensional measurement of a first magnetic field generated by a power cord to supply power to a device; and determining, via the processor, an operational status of the device based on the first multi-dimensional measurement.