NDA-24296 CHAPTER 2
Page 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 located in the PIM. The -48
V input power source, which is converted to +5 V, -5 V, and +12 V, is distributed to each circuit card in the
associated PIM. This card also has a Ringing Generator Unit (RGU), whose output frequency and voltage
can be selected from 20 Hz, 25 Hz, 75 Vrms, 90 Vrms by switch setting on this card. In addition, a Howler
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)