MAINT (PN’s Maintenance Circuit Pack)
Issue 1 May 2002 8-1025555-233-143
8
MAINT (PN’s Maintenance Circuit
Pack)
The PN’s TN775D Maintenance circuit pack monitors and supports environmental
maintenance for PN multicarrier or single-carrier cabinets. The PN’s Maintenance
circuit pack provides switch software with a mechanism to activate or deactivate
Emergency Transfer in the PN. Control by the system of Emergency Transfer can
be overridden by the Emergency Transfer switch on the faceplate of the circuit
pack. The PN’s Maintenance circuit pack invokes Emergency Transfer when the
PN loses contact with the media server or when the PN’s Maintenance circuit
pack loses contact with every Expansion Interface circuit pack. The PN’s
Maintenance circuit pack handles loss of AC power in the PN multicarrier cabinet
by supplying battery power for 15 seconds to the PN cabinet and then an
additional 10 minutes of power to just the control carrier in the PN. When power
fails in a single-carrier PN cabinet, no such power holdover is available. In the
event that an Expansion Interface circuit pack goes insane and is reset six times
within 15 minutes, the PN’s Maintenance circuit pack will hold the Expansion
Links reset preventing the Expansion Interface circuit pack from running.
The PN’s Maintenance circuit pack has alarm LEDs which indicate the presence
of Major, Minor, and Warning alarms. A flashing LED indicates the presence of an
alarm within the cabinet. A continuously lit LED indicates the presence of an
alarm elsewhere in the system.
A management terminal (G3-MT) can be directly connected to the PN’s TN775D
Maintenance circuit pack. This link operates at 9600 bps, but system software
throttles the rate of data flow to the TN775D for display on the G3-MT to about
1200 bps. Every system command can be executed via the PN G3-MT login.
However, due to the slow speed at which the PN login operates, it is
recommended that it be used only for maintenance sessions and not for system
administration.
The media server communicates with an PN’s Maintenance circuit pack via the
following path. (Up-link messages back from this Maintenance circuit pack to the
media server take the reverse path.) Messages flow from the media server’s
processor to an IPSI-connected PN’s TN2312AP IPSI circuit pack’s Packet
Interface circuit, over this PN’s LAN bus to its Expansion Interface circuit pack,
across the fiber link to the active PN’s Expansion Interface circuit pack, and over a
serial link to the PN’s Maintenance circuit pack.
MO’s Name (in
Alarm Log)
Alarm
Level
Initial SAT Command to
Run Full Name of MO
MAINT MINOR test maintenance sh PN’s Maintenance circuit pack
MAINT MAJOR test maintenance l PN’s Maintenance circuit pack
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