Panasonic CF-29 Series Reference Manual page 74

Modem
74
NOTE
This function does not work when the computer is off or is in hibernation mode.
After operations are resumed from standby mode, the screen remains dark. The
former screen display will be restored when the keyboard, touch pad, touchscreen
digitizer, or tablet button is used.
The computer cannot resume if a telephone is connected to the line of a modem (e.g.,
a PC Card modem) other than the internal modem.