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Chapter 1: Overview September 25, 2006
1-10 LTPE-UM-3159-02
ALARMS
The EMU-830 constantly monitors each of the DSL cards for alarm conditions. When so configured, the EMU-830
provides autonomous dial-out reporting of alarms to remote management stations and printers (see “Autonomous
Dial-out Alarm Reporting” on page 1-10). The EMU-830 List 6A monitors the external 2 MHz clock supplied to the
shelf (see “External Shelf Clock Backup Circuit” on page 1-11).
The alarm status is reported in several ways: alarm LEDs, alarm relays, terminal screens, SNMP traps, and dial-out
reporting. DSL card alarms can be specified as major, minor, or disabled. Shelf alarms can be specified as major,
minor, critical, or disabled. A major alarm is asserted when an alarm condition occurs in a card or shelf that is
specified as major. A minor alarm is asserted when an alarm condition occurs in an DSL card or shelf that is
specified as minor. Only shelf alarms can be classified as critical. A critical alarm is asserted when any shelf alarm
occurs that is specified as critical. Use the TAO Main menu to login to an DSL circuit to configure the DSL card
alarms (see “Config Menu” on page 3-8).
Six alarm relays are provided for use with external alarm indicators such as lights or buzzers. Each relay is a form C
type which provides three contacts: Common, Normally Open, and Normally Closed. An alarm relay diagram is
shown in Figure 1-7.
Figure 1-7. EMU-830 Alarm Relay Diagram
The six alarm relays are:
1. Critical Visual
2. Critical Audible
3. Major Visual
4. Major Audible
5. Minor Visual
6. Minor Audible
Additionally, a System ID relay is activated when any minor, major, or critical alarm is active in the shelf.
The Critical Visual and Critical Audible alarm relays and the System ID relay operate in the fail-safe mode. That is,
when power is lost to the EMU-830, the Common contact connects to the Normally Open contact.
The ACO (Alarm Cut-Off) function is used to retire active alarms by resetting the minor, major, and critical alarm
relays (both visual and audible). The Shelf Alarms menu (page C-16) can be used to program which alarm relays
will and will not be retired when ACO is engaged. ACO can be activated by pressing the front panel ACO switch or
by connecting the external ACO input (pin 25 of the Alarm connector on a shelf) to ground. ACO is deactivated when
there are no alarms or when a new alarm occurs.
AUTONOMOUS DIAL-OUT ALARM REPORTING
When connected through a modem to a dedicated telephone line, the EMU-830 can dial-out to a remote
management station or printer to autonomously report DSL card and shelf alarms. For the EMU-830 to perform this
function, you must first configure the EMU Modem Parameters, set the severity of the Shelf Alarms, and enable the
Remote Alarm Reporting option (see page C-14 through page C-17).
Normally Closed
Normally Open
Common