Compaq EN Series Technical Reference Manual page 75

Chapter 4 System Support
SMI- Generation
The SMI- (System Management Interrupt) is typically used for power management functions.
When power management is enabled, inactivity timers are monitored. When a timer times out,
SMI- is asserted and invokes the microprocessor's SMI handler. The SMI- handler works with
the APM BIOS to service the SMI- according to the cause of the timeout.
Although the SMI- is primarily used for power managment the interrupt is also employed for the
QuickLock/QuickBlank functions as well.
4-26 Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition - September 1998