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FUNCTION
D7h
-
Get
or Set Error
Tone
Values
AX
BX
CX
DX
SP:
BP:
SI:
Dl:
IP:
FLG
CS
DS
SS
ES
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Entry:
AH
AL
BX
CX
DX
D7h
(function
code)
=
Get,
1
-Set
Tone
channel
number
Error
tone frequency
Error
tone
duration
(2.5
msec
increments)
Exit:
none
This
function
is
used
to
set the
frequency
and
duration
of
the
error
tone
sounded
when
function
D6h
is
executed.
The
frequency
is
specified
in
Hertz
and
is
passed
in
CX.
The
duration
is
specified
in
2.5 millisecond
increments
and
is
passed
in
DX.
Setting either
the
frequency
or
the duration
to
disables the
error tone.
If
AL
is
on
entry,
the current
settings
are
returned.
If
AL
is
1
on
entry,
the specified
values
are
set.
There
are 5 tone
channels
provided,
numbered
0-4.
Channels
and
1
are
reserved
for
use by
Microsoft applications,
and
should
not
be
used.
59
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