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dtmStartTrunkMonitor

Description

Starts monitoring a specified trunk.

Prototype

DWORD dtmStartTrunkMonitor ( CTAHD ctahd,
unsigned board,
unsigned trunk,
DTMHD *dtmhd, DTM_START_PARMS*parms)
ctahd Handle returned by ctaCreateContext.
board AG board number, as specified in the configuration file.
trunk The specific trunk on the board. The first trunk is 0.
dtmhd Pointer to the returned monitor handle.
parms Pointer to a parameter structure. Set this to NULL to use default values. The DTM_START_PARMS structure is: typedef struct { DWORD size; DWORD maxevents; DWORD reportmask; } DTM_START_PARMS;

Return Values

SUCCESS
CTAERR_FUNCTION_ACTIVEAlready monitoring the specified trunk in the current CTA context.

Events

DTMEVN_MONITOR_DONEMonitoring ended. The size field contains board number in the high word and trunk number in the low word. The value field of the event contains an error code.
DTMEVN_MONITOR_STARTEDMonitoring started. The value and size fields are the same as for DTMEVN_TRUNK_STATUS.
DTMEVN_TRUNK_STATUSThe value field contains a four-byte DTM_TRUNK_STATE structure. When the trunk is operational, all bytes are set to 0. The size field contains the dtmhd.

Details

This function starts monitoring a particular digital trunk and returns a DTM handle, dtmhd. Monitoring is active until it is stopped with dtmStopTrunkMonitor, or until the DTM service is closed, or until the CTA context associated with ctahd is destroyed. The dtmhd is valid until the application receives the DONE event from the call to dtmStopTrunkMonitor.
dtmStartTrunkMonitor can be called multiple times on the same CTA context for different trunks. Also, the same trunk can be simultaneously monitored by multiple CTA contexts.
parms points to a DTM_START_PARMS parameter structure. If parms is NULL, default parameter values will be used. Use CT Access' parameter management functions to change default parameter values for a processing context.
The fields in the DTM_START_PARMS structure include: maxevents, which defines the maximum number of status events that the DTM service can generate in a one second interval. Its default setting is 1. If status changes occur after the event limit is reached, there will be an event at the beginning of the next one second interval. Events that are solely the result of changes in the errored seconds counters are not included in the event limit. reportmask, which controls when the DTM services sends events. Its default setting is 1. It can be set to any of the following values: Value Send events... 0 Only in response to dtmRefreshTrunkStatus. 1 Only when going in or out of alarm (ignoring type). 2 On any change in received alarms. 4 On any status/synchronization change (including Loss Of Signal). 8 On any slip. 0x10 On change in errored seconds counter 0x20 On change in failed seconds counter 0x40 On change in severe errored seconds counter
An application that is only interested in knowing when a trunk fails and when it is restored, should use the default value of 1 for reportmask. Set reportmask to 0x7F to get events when anything changes.
A DTMEVN_MONITOR_STARTED event, containing the current alarm status, will always be sent as soon as the monitoring is started.
dtmStartTrunkMonitor fails if the board type does not support monitoring.

See Also

dtmStopTrunkMonitor

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