12 System architecture
receive output simultaneously. A terminal may be configured as an input
only or
output
only device.
Overlay programs provide the system interface for maintenance, service
change, and traffic measurement. Each overlay program is independent and
has its own specific set of commands and formats. Overlay programs may
be run concurrently with normal call processing without interfering with
system traffic. There are five main categories of overlay programs:
Service Change and Print Routines
Service changes do not generally require hardware intervention. Instead,
the service administration programs are used to create or modify all aspects
of the system from individual feature key assignments to complete system
configurations. There are also programs and print routines for retrieving the
data from the system to check the status of office data assignments.
Maintenance Diagnostics
These programs are the primary instruments for maintenance purposes.
Individual programs are used for automatically or manually testing the CE
and PE. The programs may be loaded into the overlay area at the request of
maintenance personnel, or as part of a daily maintenance routine
automatically initiated by the system at a specified time. In addition,
background and signaling diagnostic routines can occupy the overlay area
-.-
when it is not in use.
Traffic
All systems are equipped with traffic data accumulation programs. There is
also a resident traffic print program which examines the schedules, transfers
data from accumulating to holding registers in accordance with schedules,
and prints the traffic data. In addition, there is a traffic overlay program
which is used to query and modify schedules, options, and thresholds.
Equipment Data Dump
After making service changes, the changes must be transferred to disk in
order to save them. When the equipment data dump program is invoked, all
the office data in the read/write memory is written to the system disk. The
data dump program is also used to install a new generic version or issue and
capture protected data store information which may be changed by the user,
such as speed call lists. The program may be invoked automatically during
System overview 553-3001-l 00