SPDIF is a perfect way getting the Toaster to software, but too often there is problems with interfaces, clicks, noises, … ! When using newer Mac models the input of these models also offer optical digital input. So here´s the easy way using this way:
Get a digital rca cable (cinch) from Toaster SPDIF output, and a Lindy audio converter. http://goo.gl/kQcMV7 From Lindy to Mac use a toslink cable with a mini plug (or adapter) on Mac side. Plug that mini plug into Mac input!
Using Logic you can now use lowest latency mode (32, 4,8ms) with no clicks, or any noises, and even software monitoring with that mode works "like a charme"!
Finally I can use SPDIF now without any problems, may be this info can help some of you, because no expensive interface needs to be used, and even with an expensive interface there still might be problems!