# Opal Classes

Classes in the list immediately below are the most important. They are the base classes of the protocol specific classes used:

- OpalManager
- OpalEndPoint
- OpalCall
- OpalConnection
- OpalMediaFormat
- OpalMediaStream
- OpalTranscoder
- OpalListener
- OpalTransport

Some of these classes (OpalConnection, OpalEndPoint) will have a descendant created for every protocol supported by this library. Other classes (OpalManager) will not need a descendant created for each voip protocol supported.

A simplified API is available via the class:

- OpalContext

Various other important Opal classes are listed below.

- OpalTransportAddress
- OpalMediaPatch
- OpalLineInterfaceDevice
- OpalMediaOption
- OpalRFC2833Proto
- OpalSilenceDetector
- OpalVXMLSession
- OpalWAVFile