Nortel DMS-100 Series Maintenance Manual page 39

The alarms card also functions to
• monitor and control the distribution of power to the power converters,
ringing generator cards (-48 V from the circuit breakers), and the line
drawer units (+5 V, +15 V, and -48 V ringing signals through fuses)
• control the major alarm circuit which activates the MAJ LED on the FSP
and operates the major scan point, the fuse alarm scan point, and major
alarm signal distribution points. The major alarm activates when
— any fuse blows
— the RCP card signals the alarms card of a major alarm condition
• control the critical alarm circuit, which activates the CRIT LED on the FSP
and operates the critical scan point and signal distribution points to the
main distribution frame (MDF). The critical alarm activates when
— the circuit breakers (00 and 10) for power converter are turned OFF
— both RCP cards are disconnected from their card slots
— the RCP cards signal the alarms card of a critical alarm condition
— there is no output from at least one of the talk battery circuit breakers
Maintenance and fuses card (NTTR75AA)
The NTTR75AA maintenance and fuses card is in the front of the FSP. The
maintenance and fuses card contains
• 66 fuses that protect -48 V, +15 V, and +5 V power to the line drawers, -48
V to UMPs and LEDs, ringing voltage to line drawers, and the alarm
battery supply (ABS) that
— connects the power source (the power converters) with the power
destination (the line drawers and UMPs)
— connects to the alarms circuit for monitoring
• the critical, major, minor, and ABS LEDs
• the RCP RS232 connectors that allow communication with external
monitors
• two telephone jacks
• four test points (-48 V ABS, -48 V A-feed, -48V B-feed, and BTRN
[battery return]) test points
RS232 connectors Two RS232 9-pin connectors are on the face of the FSP.
Each connector connects to one of the RCP cards. These RS232 connectors
enable maintenance personnel to access PMDEBUG through a personal
computer (PC) and get information without having to access the host MAP
terminal in the host office. In the field, operating company personnel must
DMS-100 Family NA100 Star Remote System XPM15 and up
Star Remote System hardware 2-19