CHAPTER 2 NDA-24296
Page 66
Revision 1.0
PA-PW55-B
Power

PA-PW55-B

Power

1. General Function
The PA-PW55-B (PWR) circuit card supplies operating power to circuit cards accommodated in the PIM.
The -48V input power source, which is converted to +5V, -5V, and +12V, is distributed to each c ircuit card
in the associated PIM. This card is also equipped with a Ringing Generator Unit (RGU), whose output
freq uenc y and v ol tage can be select ed among 20Hz, 25Hz, 75Vrms, 90Vrms b y swi tch se tti ng on this c ard .
In addition, a Howler Tone circuit resides on this card.
Figure 2-22 Location of PA - PW55-B (P WR) 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-B (PWR) PA-PW54-B (DPWR)
-48 V (Fo r LC, TRK)
DC-DC
RGU
HOW
SUB
PWR
REL
NFB
-48 V
+80V (Option) Note
+80 V (For MWL)