NTP
                           NTP 297-1001-100                  PAGE 15
                          PREL., ISSUE 01D03
                               79 09 21



  6.   MAINTENANCE SYSTEM


  6.01    The  DMS maintenance  system  is  designed to  detect  and
  analyze  faults,  to take  corrective  action,  and to  alert  the
  maintenance personnel.  The maintenance  system is responsible for
  maintaining both  the software and  the hardware resources  of the
  DMS switch.

  6.02    The   maintenance  system   is  subdivided   into  several
  subsystems, each  of which  is responsible  for its  own level  of
  hardware.  The responsibilities of each subsystem include:

       a)  routine testing,
       b)  fault detection,
       c)  fault analysis,
       d)  error  reporting, diagnostic reporting,  and/or subsystem
           status reporting.

  6.03   The Maintenance and  Administration Position (MAP) provides
  an  interface  between  maintenance   personnel  and  the  various
  maintenance subsystems. It provides maintenance personnel with the
  information  and  tools  necessary  for  efficient  diagnosis  and
  identification of system faults at a  level where the fault can be
  corrected by the replacement of a card.

  6.04   Current status information about the system is displayed on
  a  Visual Display  Unit (VDU)  associated with  the MAP.   Various
  levels of system  status information can be  accessed via commands
  input at the  VDU.  The requested information is  displayed on the
  VDU screen.

























                  DMS-100 FAMILY SYSTEM DESCRIPTION
                  (c) NORTHERN TELECOM LIMITED, 1978