Thermal Expansion itemducts answered

[Ryan Mesure]

Ok dumb question, when you wrench the itemducts on TE, what is each arrow. Blue and red, which one is input and which is output. Does it matter if the machine can only output.

 

[hiroshi42]

Blue is input red is extract but either needs a redstone signal or a servo right clicked onto it so you can tell it to ignore redstone. The extract mode can sometimes interfere with blocks that auto-eject although this is more noticeable with fluids. Not sure about what you are asking with the last question.

 

[Adonis0]

The trick is to look at the little triangle on it and figure out which way it's pointing
Blue will always point towards the block it's connected to (I.e. Input)
Red will always point away (I.e. Output)

You can tell if the red is extracting items itself as it will be a bright red instead of a dull red

EDIT: Yes it matters if the machine can only output, but you don't need to power the output, just so long as it's not blue.

 

[Ryan Mesure]

thanks wanted to rule that out

 

[kaovalin]

thanks wanted to rule that out

When the item duct is set to output mode (dark red arrow) it will allow machines that normally output automatically to do so without the item duct needing a redstone signal (making it a bright red arrow). The advantage to applying a redstone signal is that the duct will extract up to a whole stack at a time.

You may also like that if you right click with a wrench (no sneaking) that you can configure that section of pipe to be in round robin mode. This will evenly distribute what comes out of that to the rest of the system where that item can be accepted.