NDA-24296 CHAPTER 2
Pag e 61
Revision 1.0
PA-PW55-A
Power

PA-PW55-A

Power

1. General Function
The PA-PW55-A (PWR) circuit card supplies operating power to circuit cards loca t ed in the PIM. The -48
V i nput powe r source, which is conve rted to + 5 V, -5 V, and +12 V, is dis trib uted to each circuit card i n the
asso ci at ed PIM. This card al s o has a R ing i n g Generat or U nit (RGU), w hose output frequency and voltage
can be selecte d from 20 Hz, 25 H z, 75 Vrms, 90 Vrms by switch setting on this card. In addition, a Ho wler
Tone circuit resides on this card.
Figure 2-20 Location of PA-PW55-A (PWR) Card in the System
Note: The +80V input is required for activating Message Waiting Lamps (MWLs) .
HOW (For LC)
CR (For LC)
+5V, + 12V, -5V
DC-DC
RGU
HOW
SUB
PWR
REL
NFB
PA-PW55-A (PWR) PA-PW54-A (DPWR)
-48 V (For LC, TRK )
DC-DC
RGU
HOW
SUB
PWR
REL
NFB
-48 V
+80V (Option) Note
+80 V (For MWL)