Compaq 1610 Reference Manual page 53

Your handheld PC automatically recognizes a wide range of PC
Cards approved for use with Windows CE. If you are instructed to
install card-specific device drivers provided by a PC Card
manufacturer, be sure to install only device drivers specifically
designed for Windows CE. Do not install card and socket service
enablers. If you are unclear about installation instructions, call
your PC Card manufacturer for more information.
Do not save data to a PC Card when the batteries on your
handheld PC are low, as this can result in loss of data. Be sure
the batteries are in good condition or connect to external
power before attempting to save your data.
Do not turn off your handheld PC while the PC Card is
performing an operation (such as saving data), as this can
result in data loss.
Do not eject a PC Card while it is performing an operation, as
this can result in data loss.
Do not expose the PC Card to dirt, moisture, or liquids.
Always carry PC Cards in protective cases or sleeves when
they are not being used.