Two forms of call parking are provided: directed call park and non-directed call park. In directed call park, the application specifies the destination address where the call is to be parked. This roughly behaves like a call transfer to the destination address, but it doesn't alert or time-out as a transfer would.
In non-directed call park, the switch returns to the application the address where it parked the call. In either case, the linePark function is used to park a call. A parked call can later be retrieved with lineUnpark. The application specifies the park address to lineUnpark that returns a call handle to the unparked call. Appropriate LINE_CALLSTATE messages will be sent to the application as the call is reconnected.