AT&T 3B2/300 Technical Reference Manual page 432

- - - - - - - - - - - - - - - - - - - - - - - - - - - FUNCTIONAL DESCRIPTION
System Failure Detection and Alarm Generation
All alarm stimuli are gated into one of the two alarm outputs from the AIC card. Ultimately, one of
these alarm stimuli will induce current flow in one of the opto-coupler devices. One coupler is
dedicated to providing closure for major alarms, the other is for minor alarms.
Major alarms are caused by software command, second sanity time-out, AC failure and low battery
condition, or an external input which is user defined. Minor alarms are caused by software command,
AC failure indication, or external input which is user defined. The following table defines the types of
alarm stimuli and the resulting action.
ALARM STIMULUS ACTION TAKEN
SW SET SWMAJORl
Major alarm sent to autodialer and recorded
in Status Register. No other machine action.
SW SET SWMlNORl Minor alarm sent to autodialer and recorded
in Status Register. No other machine action.
HW SANITY TIMEOUTl PINT20 asserted over
1/0
bus and recorded
separately in AIC CSR bit 10. No alarm or
other machine action.
HW SANITY TIMEOUT2 Major alarm sent to autodialer, INSANEl latched
in AIC CSR, RQRSTO asserted (not latched) over
1/0
bus to bring system down (and back up under
software option).
3B2 DC POWER FAILURE Major alarm sent to autodialer. No other machine
action. CSR invalid.
COMMERCIAL AC FAILURE
Same as 3B2 DC power failure.
AT 3B2 INPUT (NO UPS
INSTALLED)
COMMERCIAL AC FAILURE No AIC hardware detection of AC loss. No
AT 3B2 INPUT: UPS WITH
action taken.
NO AC CLOSURE ABILITY
INSTALLED
COMMERCIAL AC FAILURE ACFA!Ll latched in CSR. Minor alarm
AT 3B2 INPUT: UPS WITH sent to autodialer.
AC FAILURE DETECTION
INSTALLED
EXTENDED AC FAILURE
UPS provides closure on Low Battery lines
AT 3B2 INPUT SUCH THAT which is logged in AIC CSR bit LOWBATI. If
BATTERIES BECOME LOW ON ACFAILl is also set, PINT20 is asserted over
A UPS WHICH HAS AC LOSS the 1/0 bus to bring the system down and a
AND LOW BATTERY DETECTION
major alarm is sent. If ACFAJLl is not sent,
AND CLOSURES
only the Low Battery CSR bit is latched.
LOW BATTERY CLOSURE
LOWBA Tl latched in CSR. No other machine
ONLY, FROM UPS WITH action unless ACFAILl is active. (See above)
LOW BATTERY DETECTION
FUNCTIONAL DESCRIPTION 3-179