| 摘要 |
A portable, hand-held data terminal of modular structure includes a base module with a keyboard and a display screen. A data collection and communications module includes a stacked arrangement of a communications interface main circuit board, a radio and a laser scanner assembly which are housed in a housing shell which is attachable to the base module. The radio is mounted in spaced relationship to one side of the main circuit board, while the laser scanner assembly is mounted to the other side of the main circuit board. A support frame and a plurality of ground planes in the sandwiched main circuit board and a routing circuit board form an RF cage for shielding RF interference which may be generated by the radio. Also disclosed is a method for reducing the operational power consumption requirements of laser bar code scanners by analyzing reflected laser light in order to determine the presence of optically readable information sets. In a first embodiment, the reflected light intensity of a pulsed laser light beam is compared to the ambient light intensity to provide a control signal to actuate the scanning mode if a threshold differential is satisfied. In a second embodiment, a modulated laser light pulse is filtered to remove ambient light noise and then provides a control signal to actuate the scanning mode if a threshold value is reached.
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