When in the Sound In section of the Sound control panel, the Options button is disabled (it appears dimmed or "grayed out").

The Options button was added to the Sound control panel to provide a place for users to control access to sound channels and the Playthrough option. The affected models listed below were released before these options were put into use.

The systems that exhibit this behavior are:

* Performa 475/476
* Quadra 605
* Centris 610
* Centris 650
* Quadra 610
* Quadra 650
* Quadra 800

When these computers were released, the CD-ROM drive was set up to always play audio CDs through the built-in speaker (or the sound out port). The CD player was chosen as the sound source whenever the microphone was not plugged into the Sound In port. In other words, the features that you control by clicking on the Options button are controlled automatically on these systems.

There is no way to let these systems control their sound channels and playthrough options using software, like other Macintosh systems do. That is why the Options button has been disabled.