If you looked at the 2-slot directly the ACS is on right, or directly on the backboard as originally mounted. The Avaya docs show that you then just place 308ec on it and the 2 slot plugs into it.

That would be correct- with two screws to hold the carrier to the mods and hold the top mod in place. However I always assemble it first then use long #8 screws through the top and bottom of both mods to screw it to the backboard. Makes it a lot easier to change a mod out later on because you aren't taking it apart on the wall. Just pull the cables and remove the screws.

The backplanes are different sizes so it only can go one way.

They are card edge connectors not backplanes. I was going to mention the sizes. With the older carriers both were the same, the newer ones the processor connector was larger because the ACS had a larger card edge. So you are OK on both counts. Try the 5 slot and if that still doesn't work either the ACS or the 308EC is bad. This is refurbed so none of that should be unexpected.

-Hal

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