property DeltaRI : Boolean
Returns True if the port's "delta ring indicator" (DeltaRI) bit is set.
DeltaRI is set only if RI (the ring indicator) has changed since the last time the application called CheckDeltaRI.
The formal name for this bit is "trailing edge ring indicator" or TERI. DeltaRI is used for consistency with other Async Professional CLX naming conventions.
It is generally better to use DeltaRI to detect incoming calls than to use RI. RI toggles rapidly as rings are detected, making it easy for your application to miss the brief periods that it returns True. By contrast, DeltaRI returns True if any ring was detected since the last call to the routine.
See also: RI