of a held multiparty call might not be possible on some
implementations.
+ NOTE: Releasing active calls does not produce
+ side-effects. That is the state of held or waiting
+ calls is not affected.
+
Possible Errors: [service].Error.InProgress
[service].Error.Failed
[service].Error.NotImplemented
This is usually implemented using the ATD AT command.
+ NOTE: If an active call (single or multiparty) exists,
+ then it is automatically put on hold if the dial
+ procedure is successful.
+
Possible Errors: [service].Error.InProgress
[service].Error.InvalidArguments
[service].Error.InvalidFormat
void HangupAll()
- Releases all calls.
+ Releases all calls except waiting calls. This includes
+ multiparty calls.
Possible Errors: [service].Error.InProgress
[service].Error.NotImplemented