Open Line
Associated with: PSTN outstations or outstations with PSTN fallback; Slave PSTN outstations
Security permission required to access this pick action: Retrieve Data
With systems on which telephone call duration costs do not apply, an Open Line call is sometimes used instead of a One Shot call. Use the Open Line pick action to instigate such a call.
With an Open Line call, ClearSCADA maintains communications with the outstation for a specified time, even if the server has retrieved the outstation’s data before that length of time is reached. The time for which the line remains open is specified on the PSTN tab of the Outstation Form (see Define an Outstation’s PSTN Properties in the ClearSCADA Guide to Advanced Drivers).
If supported by the outstation type, you can use the Extend Line pick action to extend the call.