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Power SuppliesPassport 4400 Hardware Installation Manual
9-4
DC Power Supplies
The DC power supply system allows the Passport 4400 unit to be installed in a
telephone company environment with the necessary DC power input being
furnished by the telephone company to the input of the Passport 4400 unit.
Note:
The Input Connectors on the DC power supply are located at
the side of the power supply closest to the edge (see Figure
9-2 and Figure 9-3).
The -48 volts DC version of the Passport 4400 unit power supply system is
identical to the AC version except for the addition of a terminal power adapter
that plugs into the line cord Electronic Industry Association (EIA) jack on back
of the unit. The five power supplies stack identically to the AC version. The
connectors accept the same cables for input and output power.
The DC input voltage must be within the range of -32 volts DC and 72 volts DC.
The plus (+) and minus (-) markings on the input power adapter box indicate
the polarity of corresponding battery connections. They are electrically floating
and can either be connected to house ground or the appropriate DC return. An
additional case ground screw is also on the power adapter box. This connection
must be grounded to the chassis safety ground for safety and electrical noise
suppression. Do not operate the unit without the ground screw connected to the
safety ground.
Figure 9-5. DC Power Supply
E
D
C
B
A
-48
+48
Return
Chassis
+48 VDC (Return)
-48 VDC
Chassis Ground
Safety
Plastic Door
Terminal Block
Junction Box for 48 VDC
Power Supply