User`s guide

136 DC 900-1340I
BSC Programmer’s Guide
5.4.1.15 BSC 2780/3780 Trace using dlWrite
The following trace commands allow a client application program to monitor line
activity. Refer to the Freeway Data Link Interface Reference Guide for possible
dlWrite
error returns.
Start Trace
Use the dlWrite function with the pOptArgs.usProtCommand field set to
DLI_PROT_START_LINK_TRACE to send a BSC 2780/3780 Start Trace command. After start-
ing the trace, the BSC 2780/3780 software responds with a start trace confirmation with
the
dlRead pOptArgs.usProtCommand field set to DLI_PROT_START_LINK_TRACE. If you issue a
Start Trace command to a link that already has trace enabled, you will receive another
start trace confirmation.
Stop Trace
Use the dlWrite function with the pOptArgs.usProtCommand field set to
DLI_PROT_STOP_LINK_TRACE to send a BSC 2780/3780 Stop Trace command. This com-
mand terminates link trace. After stopping the trace, the BSC 2780/3780 software
responds with a stop trace confirmation with the
dlRead pOptArgs.usProtCommand field
set to
DLI_PROT_STOP_LINK_TRACE.
Link Trace Data
After trace is enabled, the BSC 2780/3780 software sends the link trace data to the client
with the
dlRead pOptArgs.usProtCommand field set to DLI_PROT_LINK_TRACE_DATA. Link
trace data is reported to the client each time a data transmission or reception event
occurs, in the order of its occurrence. The BSC software queues trace data messages up
to the queue limit (Section 6.19 on page 175) before sending the
DLI_ICP_ERR_QFULL error
to the client.
Link trace data always includes time, line mode, and event. If the event was a data block,
the trace also includes the length of the data, followed by the actual data (the data length