Collecting And Storing Data - Northern Telecom DMS-100 Series Maintenance Manual

2-6 DPP system operation

Collecting and storing data

MTD and storage type output signals from the DMS-100 are routed from the
active DMS-100 MTD port, through the interface box, to the DPP DSI
PCAs. The DSI PCAs have their own microprocessor and software program
to emulate MTD functions. These functions require two-way
communication between the DPP and the DMS-100. The DSI software
receives the commands that are normally sent to the MTDs, and responds
with the status and strobe signals normally sent back to the DMS-100. The
DSI receives call record data blocks, processes them and forwards them to
the active processing unit.
When data blocks are received from the DMS-100, a signal is sent to the
active processing unit to take the data block. Under processor (DMA)
control, the data block is transferred through the data bus and assigned to a
buffer. The buffer used depends on whether the block contains test or call
record data. Test data blocks may be read back to the DMS-100, but not to
disk. The DPP software program stores test blocks on the DSI PCA. A six-
block buffer in the main CPU holds call records where validation occurs.
During the validation checks, all criteria relative to validation, thresholds,
and alarms are used in examining the data block. If a call record, a group of
call records, or the entire block does not meet the validation requirements,
an exception report is printed out as a log message. In extreme cases, a
processor alarm is generated.
Validated call records are loaded into a disk buffer for each call record type.
These buffers are located on the Disk Interface PCA. When a buffer is full,
it is written to disk, while the other buffer is made available to receive call
records.
Ribbon cables send data, plus write commands from the Disk Interface PCA
to the Disk Crossover PCA and both disk drives. Identical data is written to
the primary disk, then to the secondary disk, providing redundancy to
enhance the integrity of the billing data.
297-1001-537 Standard 01.02 December 1993