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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127
Issue 1
August 1997
Circuit Packs and Power
Page 2-7Power
2
NOTE:
When EPN power is interrupted for greater than the cabinet holdover but
less than the control carrier holdover, calls in the control carrier are held for
the duration of the interruption but are dropped when power is restored.
Single-Carrier Cabinets
In single-carrier cabinets, there is no internal AC wiring or distribution and no
software interaction with the power system. The power supplies themselves take
about 250 milliseconds for the voltages to drop below limits.
The control cabinet that houses the Switch Processing Element (SPE) is the only
cabinet that has an internal battery reserve. All other control cabinets and port
cabinets have the 250 millisecond power supply decay delay, after which all
connections and links associated with the cabinets are dropped.
1. The holdover times listed are in effect if the EPN contains a TN775 maintenance circuit pack.
However, if the EPN contains a TN775B maintenance circuit pack, the holdover time for the entire
cabinet is 10 seconds, and the holdover time for the control carrier is 10 minutes.
Table 2-3. Response to Power Service Interruption with an Internal Holdover Battery
System and
Configuration Cabinet
Holdover for
Entire Cabinet
(in seconds)
Holdover for
Entire Control
Carrier (in minutes)
Standard PPNMCC 10 10
High, Critical PPNMCC 10 5
Standard/High, Critical PPN SCC/ESCC 1/4 2
Standard/High, Critical
1
EPN MCC 15 none
Standard/High, Critical EPN SCC/ESCC 1/4 none
Table 2-4. Types of Cabinet Power Interruption
System and
Cabinet
Shorter Holdover
Than Entire
Cabinet
Longer Holdover than
Entire Cabinet, Shorter
Holdover than Control
Carrier
Longer Holdover
Than Control
Carrier
PPN SCC No calls dropped All calls dropped System reloads
EPN SCC No calls dropped All calls dropped System reloads