Function 18, subfunction 8 - disable/enable the internal speaker.

If speaker sound is disabled, all calls to subfunction 55 of function 55 are ignored. If speaker sound is enabled, they are routed on builtin speaker.

Subsubfunction 1 - get status.

Parameters: Returned value:

Subsubfunction 2 - toggle status.

Toggles states of disable/enable.
Parameters: Returned value: