Device Swap Signal; Device Fault Signal; Replacing An Emu - Compaq 4200 User Manual

This signal is asserted (high) when all the power supplies and blowers are operating
properly. Should any power supply or blower be operating outside of a specified range this
signal level is low until the fault is corrected.

Device Swap Signal

This fault bus signal (SWAP) detects the removal or insertion of a storage device on a
SCSI bus causing the signal to generate a logic low pulse. The SWAP signal for each SCSI
bus indicates a change in the status of the storage devices on that bus.

Device Fault Signal

The EMU can control the device status LEDs in the following manner:
When the controller detects a device fault, it can cause the EMU to F
device status LED at a fast rate.
The controller can cause the EMU to F
to identify or "locate" a device.

Replacing an EMU

To replace an EMU, you must complete the procedures outlined in Chapter 6, "Replacing
CRUs."
Environmental Monitoring Unit
a specific device status LED at a slow rate
LASH
4–5
the specific
LASH