Aftermarket 1747-UIC problem

I purchased an aftermarket 1747-UIC and it works great when plugged directly into an SLC500 processor or connected to the trunk line of a DH-485 network. I can't seem to get it to work when connected to the peripheral port of a 1747-AIC link coupler as described in A/B 1747-AIC instructions. I have experimented with swapping the Tx and Rx leads between the peripheral port and the UIC as well as the trunk line feeding the AIC but nothing I tried has worked. Does anybody know of a fix for this problem??

How are you powering the AIC?

external 24VDC power supply. Also tried using the peripheral port on an AIC powered from a 5/03 processor with no luck