HP 3100C - Manual (Page 74)

Environmental ranges 73
Environmental ranges
CAUTION The operating environment should be stable, with no abrupt changes
in temperature or humidity, or your digital sender might be damaged.
If you move the digital sender from a cold to a warm environment, wait
about two hours before using it.
Temperature
Operating 10 to 35° C (50 to 95° F)
Storage -40 to 60° C (-40 to 140° F)
Humidity
Operating 10 to 80% noncondensing (10 to 35° C)
Storage 0 to 90%