User Manual

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2.9 Real-Time Clock Subsystem
A coin-cell battery (CR2032) powers the real-time clock and CMOS memory. When the computer
is not plugged into a wall socket, the battery has an estimated life of three years. When the
computer is plugged in, the standby current from the power supply extends the life of the battery.
The clock is accurate to  13 minutes/year at 25 ºC with 3.3 VSB applied via the power supply 5 V
STBY rail.
NOTE
If the battery and AC power fail, date and time values will be reset and the user will be notified
during the POST.
When the voltage drops below a certain level, the BIOS Setup program settings stored in CMOS
RAM (for example, the date and time) might not be accurate. Replace the battery with an
equivalent one. Figure 4 shows the location of the battery.
2.10 LAN
The onboard LAN controller consists of the following:
• Intel Gigabit Ethernet Controller i225-LM (10/100/1000/2500 Mb/s)
• RJ-45 LAN connectors with integrated status LEDs
Additional features of the LAN subsystem include:
• CSMA/CD protocol engine
• LAN connect interface between the Processor and the LAN controller
• Power management capabilities
― ACPI technology support
― LAN wake capabilities
• LAN subsystem software
Figure 5. NUC 11 Extreme Kit LAN Controller Layout