[pulseaudio-discuss] want to know how to prevent pulse audio from connecting to an external USB sound card

[David Henningsson]

On 12/28/2012 02:54 PM, Bill Turner, WB4ALM wrote:
> I am a Radio Ham, and have an external USB sound card (SignaLink USB)
> that functions as a control device for one of my Radio Amateur
> Transmitters.  The Signalink USB acts as an interface between the
> transceivers mike input and speaker output and allows me to encode and
> decode digital signals sent over the air with any of a series of
> computer programs. (I prefer the use of "fldigi")
>
> I have had the Signalink for about a month, and it works great - EXCEPT
> when pulseaudio "attaches" it as an audio card to be controlled...
>
> I can not figure out how to keep my Ubuntu 12.10 system from
> interferring with the intended use of this card.

If you know how to write udev rules, the recommended way to go is to 
write one to tell Pulseaudio to ignore your card by setting 
ENV{PULSE_IGNORE}="1".

Look at /lib/udev/rules.d/90-pulseaudio.rules for inspiration. We have a 
rule there for ignoring a strange sound card created by the 
thinkpad-acpi driver.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic