Common Systems Connection Standards AT&T Services, Inc
Date: August 31, 2007 ATT-TP-76450, Issue 9
Copyright ©2004 – 2006, AT&T Knowledge Ventures
All rights reserved
Page 14
Footnote: The term "Network Element" is used within this document to refer to any and all
equipment other than switching equipment deployed in a CO or remote location. This would
include, but is not limited to transport, conditioning, power and testing equipment as well as
environmental and building operations sensors.
4.3 Separation of Local Alarms
• Local alarms must be separate alarm outputs from the telemetry alarms. At a minimum
this would be a Major (MJ) and Minor (MN), both audible and visual. The visual alarm
output must be designed so it cannot be disabled with an alarm cut-off (ACO).
4.4 Audible Alarm Cut-off (ACO)
A local control button shall be provided for local office audible alarm cut-off (ACO).
• A local control button shall be provided for local office audible alarm cut-off (ACO).
• The ACO function shall simultaneously silence all active office audible alarm indications.
• The ACO function shall not inhibit office visual alarms, or subsequent audible indications
due to additional failures.
• If all previous alarms have been ACO’ed, and a new alarm becomes active, then the
ACO condition shall be cleared and the highest severity audible alarm contact shall be
activated.
• An amber LED shall be associated with the ACO button to indicate the current status of
the ACO. If active office audible alarm indications are cut-off due to execution of the
ACO, the ACO LED shall be lit indicating that the alarm condition exists and that all
active alarms of the system have been ACO’ed. The ACO LED stays extinguished if
there are no active alarms when the ACO is executed. The ACO LED is extinguished
when all active alarms clear, or when a new alarm is activated in the system, thus
clearing the ACO condition.
• As an optional feature, equipment may provide capabilities to remotely activate the ACO
function.
4.5 Telemetry Alarm Protocols:
Table 4-1 is included for reference only.
Table 4-1
TL1 / TCP-IP Most Preferred
TL1 (sync) X.25 Second Most
Preferred
TL1 (async) Third Most Preferred
BACnet/Modbus/LonT
alk
Fourth Most
Preferred
E2A Serial Fifth Most Preferred
