iMac Speakers not playing sound output?

[dalvin200]

I've just gotten the Aego-M 2.1 speaker system, and when i connect the 3.5mm jack into the line in socket on my iMac, it doesn't seem to recognise it, and just continues to play sound thru the internal speakers.

But if I connect the 3.5mm jack into the headphone socket on the iMac, the speakers work - but i'm pretty sure it's not supposed to work this way right?

Anyone tell me what I'm doing wrong - surely the line-in should work?

Thanks

 

[stillwater]

The line in is for connecting external audio sources.

The headphone port is the correct jack for audio out.

 

[dalvin200]

The line in is for connecting external audio sources.

The headphone port is the correct jack for audio out.

Ahh ok.. thanks for clearing that up