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Running VAC 4.09 on Vista & Win7 x64 (64-bit)
Running VAC 4.09 on Vista & Win7 x64 (64-bit)
Running VAC 4.09 on Vista & Win7 x64 (64-bit)
Running
VAC
4.09 on Vista & Win7 x64 (64-bit)
System Dependencies
Minimum
PowerSDR
Version:
N/A
Applicable Hardware:
All transceivers
Content provided by:
FlexRadio Systems Engineering
Virtual Audio Cable, more commonly referred to as
VAC
is a third-party software package that facilitates digital audio transfer between
PowerSDR
and other sound card enabled programs, like most digital mode programs (MixW, Digipan, MMTTY, etc.).
VAC
is able to do this because it is a kernel mode Windows device driver that emulates a sound card.
NOTE:
VAC
is a third-party software program and is not directly supported by FlexRadio Systems. FlexRadio Systems recommends its use with
PowerSDR
to facilitate digital audio transfer (DAX) between other third-party sound card programs. All inquiries in regard to the basic operation of
VAC
or concerns regarding it being unsigned (see below) must be directed to the
VAC
developers (
support@muzychenko.net
) themselves.
Windows Vista and Win7 come in two basic configurations; 32-bit or x86 and 64-bit or x64. A Windows device driver has to be the same "bit size" as the operating system, so a 32-bit operating system can only use 32-bit device drivers and 64-bit operating systems can only use 64-bit device drivers.
VAC
comes in both a 32 and 64-bit version, so from a driver architecture standpoint,
VAC
can operate on both 32-bit and 64-bit Windows operating systems.
With the introduction of Vista x64 and continued on with Win7, Microsoft imposed another requirement for 64-bit device drivers. They require all 64-bit kernel mode drivers to be signed with a digital signature in order to operate normally.
VAC
is
not
a signed driver, therefore special boot time operations must occur for the driver to
load
under Vista x64.
Please refer below to the information about running the unsigned
VAC
device driver under Vista/Win7 x64 as taken directly from the
VAC
Help file (
vac
.chm) documentation included with the
VAC
application.
From the
VAC
Installation Guide in the Application's Help System
Under 64-bit Vista, kernel-mode drivers require a publisher's digital signature to be loaded.
VAC
is not signed due to Microsoft's security policy that does not allow an individual developer to obtain a publisher certificate
. Even the installation completes successfully,
64-bit Vista displays a warning and does
not
load
the driver
. Unsigned drivers can be loaded in the "test modes" only. Please read "Installing an Unsigned Driver During Development and Test (Windows Vista)" article explaining how to enable the test modes.
There are two ways to successfully
load
VAC
driver under 64-bit Vista and 2008 Server systems:
At early boot time, press F8 and select "Disable driver signature enforcement". In this mode, Windows will not check driver signatures during current session. But
if
you reboot Windows, you should press
F8
and disable signature enforcement again. So you need to make selection at
every
boot.
Enable Windows test-signing mode by one-time issuing "
bcdedit /set testsigning on
" command from a command prompt (under Administrator account). This permanently allows Windows to
load
drivers signed by test certificates. After issuing
bcdedit
command, reboot Windows. 64-bit
VAC
driver module is signed by a test certificate named "Eugene Muzychenko (Test)" so it will be successfully loaded in the test-signing mode.
This KB article may reference additional files that are available on the FlexRadio Systems web site Downloads page. Please use the URL(s) below to download the referenced materials.
An Adobe Acrobat Reader may be required to open the file. You can download Adobe Acrobat from here.
KB Source Document(s):
None Referenced
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Details
Last Modified:
Wednesday, March 10, 2010
Last Modified By:
Administrator
Type:
INFO
Rated 3 stars based on 11 votes.
Article has been viewed 41,021 times.
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