[nst7]

I'm not sure I understand your question. Or we might be saying the same thing.

The only way to use your compressor on a pre-recorded track is to come out of any of the line outputs 1-8 (excluding whichever ones your monitors are hooked up to). Then you would go to your compressor and come back in through any of the line inputs 1 thru 4 (including 1 and 2 which can be set to line in).

The main problem is that when you are trying to use it when mixing, for a pre-recorded track, you have to use one of the available outputs that show up in the Protools software. The insert jacks on channels 1 and 2 are not available as outputs in the Protools software, so they would not be available to do that. There's no way to route any tracks to them. As mentioned, they are only for recording something on the way in.

So yes, you can use outputs 3 and 4 and come back in to inputs 3 and 4. But this has nothing to do with the insert function on 1 and 2.

I hope I've understood correctly what you were asking.