A MSX-E module provides a "system clock" that may be in the simplest case set by the function MXCommon__SetTime(). More...
If the module is configured to use NTP, the time received by the NTP server will have a greater priority. If the module is linked to another through a "synchronization bus" and is slave, then the time received from the master is the one taken into account.
Recent models also provide a "hardware clock", a component whose role is to track the time between reboots.