System Configuration User Guide

Date and Time (/dt)
syscfg {/dt | /timeofday} hh:mm:ss mm/dd/yyyy
hh:mm:ss
Hours (24 hour clock), minutes, and seconds.
mm/dd/yyyy
Month, day, and year.
Sets the time of day stored in the Real Time Clock (RTC) by the BIOS.
Examples:
syscfg /dt 18:45:00 12/20/2007
16 System Configuration Utility User Guide