Compsee Apex III, Technical Reference Manual

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Apex PDT Technical Reference Manual 3 Hardware Configuration
COAM30002 Rev. 2.00 8/13/02
3-16
BIOS Interrupt 15h - System
Function 55h, Service 00h –
Get Beeper Volume
Input:
ah = 55h
al = 00h
Returns:
Carry Flag clear if successful
ax = current setting (0 = off, 1 = low, 2 = med, 3 =
high)
Carry Flag set on error
Notes:
This function retrieves the current volume setting of the
Apex PDT internal beeper.
Function 55h, Service 01h –
Set Beeper Volume
Input:
ah = 55h
al = 01h
bx = volume setting (0 = off, 1 = low, 2 = med, 3 = high)
Returns:
Carry Flag clear if successful
ax = current setting (after change)
Carry Flag set on error
Notes:
This function is used to set the Apex PDT internal beeper
volume to the desired level.
Function 55h, Service 02h –
Volume Next
Input:
ah = 55h
al = 02h
Returns:
Carry Flag clear if successful
ax = current setting (after change)
Carry Flag set on error
Notes:
This function increases the Apex PDT internal beeper
volume from its current setting to the next higher setting.
Volume steps from high (3) to off (0).