Ok, my story is clear as mud. Sorry bout that. Let me try it this way. I built the ckt Adtran HDSL4. The midspan doubler wouldnt power. I changed the office repeater to ADC. The Adtran midspan doubler powered!!! Pretty red lights! I changed the midspan doubler to ADC also(yes, they do make an HDSL slimline 239 doubler. Product ID is SPX-HRPTSWD1) as well as the niu, and that is how the ckt is working now. ADC HDSL 4-wire with one midspan doubler. What I cant figure out is why the Adtran office rptr wouldnt power the midspan doubler (the slot had power- the office card was working) when the ADC office card that I swapped it with powered the Adtran doubler right up. Man, I just re-read this and its still hazy! Im not a good talker-person.