VOIP - SIP Client library that can handle simultaneous calls on different (soundcard) devices

I need to create an application that has multiple SIP connections and uses multiple soundcards as input / output devices. My background is C#, so .Net is preferred, but I'll work with wrappers / IKVM if necessary.

I have looked at a large number of libraries, spending most time with PJSIP (and the C# wrapper SIPEK - I've even rewritten the examples to run on Windows 7, so I've开发者_开发知识库 put in the time) .

Everything I want to achieve can be done with PJSUA / SIPEK, but it can only be done one channel at a time - opening new soundcard outputs doesn't work.

Does anyone know of either

a) A way to run multiple instances of SIPEK / PJSUA from the same interface

or:

b) A decent SDK available for .Net that has been tested for multiple simultaneous soundcards and SIP channels?

Source code available at a reasonable cost preferred, if possible.

Any ideas?

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You can use multiple devices with PJSIP, but you'll need to create multiple instances of pjmedia_conf: PJMEDIA_CONF.htm">http://www.pjsip.org/pjmedia/docs/html/group_PJMEDIA_CONF.htm