See this page for more details:Silent Way AC Encoder removes the need for a DC coupled audio interface and lets you use Silent Way with almost any audio interface. The two requirements are
* your interface must have balanced outputs (almost all do).
* you need to make some special cables.
The cables are a very simple job, well within the scope of anyone with basic soldering skills.
http://www.expert-sleepers.co.uk/siwaacencoder.html
