Soundcard Line-In vs Mic input. Difference in quality?

[AnyMal]

I was wondering if it's possible to digitize music (say cassette to PC) thru Microphone port? Is there a major difference between line-in and mic ports?

 

[RickH]

The gain and impedance of the mic input is very high, where the line input is lower in both cases. Line out from the cas into the line in of the soundcard would be a better match. R