maybe an error in the book

[davidu]

i have just bought ben's book and it is phenomenal. although i am confused with the part where i put a phonojack in? i thought a phonojack for for audio...why do i have my DC auxillary jack getting connected to it? probably a dumb question but hopefully someone can help me understand.

[jleemero]

It's probably just being used for power.

The thing is just a jack, a plug, it has no "set purpose", you could use it for just about anything that uses two wires.

So, in this case, it's being used for power, apparently.

[XCVG]

It's because Ben was kinda rushed to write the book, so he probably just said "okay this jack'll work" and used it. Don't worry about it, it's correct, just odd.