atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's Wiring from NIS to DSU ?

I'm a T1 newbie, about to wire up from my new NIS to a T1 DSU/CSU.



Based on the pinout of a 586b plug on the router end:



and



I would have wired in the NIS as:

-- #1 --
Yellow (CT1) --> Orange (pin2)
Black (CR1) --> Orange/White (pin1)
Red (CT) --> Blue (pin4)
Green (CR) --> Blue/White (pin5)

But I found a recent post that seems to indicate it should be this:

-- #2 --
Yellow (CT1) --> Orange/White (pin1)
Black (CR1) --> Orange (pin2)
Red (CT) --> Blue/White (pin5)
Green (CR) --> Blue (pin4)

So, before I screw something up, is it #1 or #2, or it doesn't matter? Thanks!

/Curt

The polarity of the pairs doesn't matter. All that matters is that you keep the transmit and receive pairs separate.

BTW: Configuration #1 is the correct one.

Thanks a bunch Ed!