Guys, I am a bit of a newbie to a lot of this and I am struggling a bit. I would appreciate some advice.

QUESTION:
Do the PC mic and line inputs use the same equalisation (on the frequency spectrum)?


BACKGROUND:
I have some noisy voice tapes from an old analogue dictation machine. I'm reading the recordings from the "ear" socket of my dictation machine into my PC and then coverting the recordings to MP3.

Later I will get some software to clean up the noise on the MP3s.

I didn't expect it but my PC allows me to set a decent recording level whether I record through the mic input or the line input. Until I clean up the sound, the noise from the original recording makes it hard to tell if I'm getting a better result from the mic input or the line input.

I wanted to know if there was a different equalisation used by the PC for the mic input compared to the line input. If so then I would make sure I used the right one.


ANOTHER QUESTION:
What is the input level at which the mic and line inputs are rated? I had thought mic inputs were about 3 or 3 mV and line inputs were 200 mV but maybe my experience above says that i snot right.

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NOTE:
My PC motherboard chipset is VIA KT266A + VT8235.
A PC reporting utility says it detects a VT8233/A AC97 Enhanced Audio Controller.

You seem to know more or less what you're asking. I'll try to clear it some more:

A microphone input is usually mono. You should take this into consideration.
Also, microphone input is usually active, while line in is passive. (A microphone will not work in a line in).

There shouldn't be any difference in the equalization of both lines, but if there is, the line in will be the flatest of both.

I assume the "ear" output of that dictation machine is where one would connect the headphones. If this is true, it is an amplified output. This is important because if you feed either mic in or line in with it, you will need to decrease the volume in order to not saturate the input.
Do not use the levels of the soundcard to level this. Use the volume on the dictation machine (i assume that if it is a headphone output, there is a volume level). The ones in the soundcard do not affect the input signal previous to digitize it.


About your second question of mV... i think that the value for line in is correct, but i don't remember, so don't take it for sure.


Edit: removed extra quote.