procedure DeregisterUserCallback(CallBack : TPortCallback);
TPortCallback = procedure(
CP : TObject; Opening : Boolean) of object;
Deregisters a component that uses TApxComPort.
This method deregisters a TApxComPort callback previously registered by a call to RegisterUserCallback. CallBack contains the address of the callback method.
See RegisterUserCallback for an explanation of a TApxComPort user and an example.