Supporting a Device

The PortCls system driver (Portcls.sys) provides several built-in port drivers to support audio devices that render and capture wave and MIDI streams.

All port drivers expose interfaces that derive from base interface IPort. IPort inherits the methods from base interface IUnknown. IPort provides the following additional methods:


Retrieves an audio adapter's Plug and Play properties from the registry.


Initializes the port object.


Creates a new registry key or opens an existing key.

PortCls implements the following port drivers:

WaveCyclic Port Driver

WavePci Port Driver

WaveRT Port Driver

Topology Port Driver

MIDI Port Driver

DMus Port Driver



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