Seems odd. Normally sound cards on Desktops will have a Mic in, Line in and Line out. It may also have a Speaker out in addition. Laptops may not have a Line IN.
In your case, it must be LINE IN and not LINE OUT. Please confirm. The CDRW audio cable goes in to the Line IN socket.
Please post a feedback.
I just bought a CD RW external drive to back up my files.
It also comes with an audio cable to plug into my computer (a left-right plug for the external drive's output that converges to a single jack for inputting into the PC's sound card). My dumb question is which of the 3 slots on the sound card does the single plug go into? There is a speaker plug, a mic plug and a line out plug. I doubt it goes into the Mic plug but I can see either of the others being appropriate.
This is not a big deal as my pc has a read-only drive that works just fine and I don't currently need to use the external drive for playing anything, but I'd still like to know (and the direction book fails to tell me).

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