Omron PS31

The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.

Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.

the variation of output frequency of a crystal oscillator due to external conditions like temperature variation, voltage variation, output load variation, and frequency aging.

a count of all of the component leads (or pins)

the maximum allowable deviation from the nominal crystal frequency at a specified temperature, usually 25℃. The recommended frequency tolerance of the crystal over the manufacturing process is ±50 ppm.