ACS-160 Series & STL-160 Series T1 Multiplexer Installation & Operation
2 – Functional Description
Version 2.11, August 2011
2-16
Harris Corporation
Intraplex Products
2.1.4.9 CM-5RTD Time Delay Common Modules
You can remotely control the delay feature on the redundant CM-5R-TD common module. However,
there are a few additional requirements for configuration of redundant time delay common modules.
The time delay function (TDLY) in the basic menu group and the time delay parameter (Topt) in the
advanced menu group must be configured identically on all CM-5R-TD configurations. Also, the SCB
address (1-36) of each CM-5R-TD must be unique. Section 4.7 –
Integrated Time Delay
has additional
details on the time delay option.
2.1.4.10 Line Failure Far-end Operation
Independent switching decisions are made at each end of the line-redundant system. Consequently, a
unidirectional failure within a T1 facility could result in a switch occurring at only one end of the
circuit. In this case, traffic would be split with outbound traffic traveling on one T1 service and the
return traffic traveling on the other – a potentially cumbersome line maintenance situation. You can
prevent this situation by selecting Yellow Alarm as a line switching criterion. After the correct
integration time, the end of the circuit that detects the line failure sends Yellow Alarm. The Yellow
Alarm, in turn, causes the other end of the circuit to switch, ensuring that both directions of T1 traffic
are on the backup T1 line. Yellow Alarm is always sent if LOS, LOF, or AIS are detected. Yellow is also
sent if UAS or BER have been selected as switching criteria and the selected error rate threshold has
been exceeded. Switching of each end of the line is completed in 500 milliseconds with LSDLY (line
switch delay) set to 0. The 500 millisecond switching periods for the two ends of the line are not time-
synchronized.
2.1.4.11 Module or Line Redundancy Alarms and Alerts
Line or module failures that result in loss of service generate a shelf Alarm (Table 2-7). A failure of the
standby module or line that does not interrupt service generates a shelf alert. A failure of the active
module or line that results in a successful protection switch action generates a shelf alert and service
continues on the backup module or line.
Table 2-7. Alert/Alarm Line Condition Dependencies
Line Condition
Alarm/Alert Indication
Condition Affects Active Line
Condition Affects Standby
Loss of frame (OOF or LOF)
Alarm
Alert
Loss of signal (LOS)
Alarm
Alert
Alarm indication signal
Alarm
Alert
BER exceeds threshold
Alarm*
Alert*
Unavailable signal state (UAS)
Alarm**
Alert**
Remote Alarm Indication (RAIS or Yellow)
Alert
Alert
Loopback
Alert
Alert
* This condition applies only if selected as a switching criterion. Otherwise, it does not result in an
alert or alarm.
** This condition applies only in AEC mode or if selected as a switching criterion in non-AEC modes.
Otherwise, it does not result in an alert or alarm.
No alarm or alert conditions are generated due to the condition of the backup T1 line if line
redundancy mode is set to “NOBK” (no backup). This setting is typically used for systems installed
without a backup T1 line.
The FTI mode is an additional Event condition mode. When operating in FTI mode, three additional
Event conditions are in effect for line redundancy.
Summary of Contents for ACS-163
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