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From your attached picture, I see you have two T1 CSU ACEs. Do both of them show EQUIPMENT LOS when connected to your PBX LD interface? That may have been what you said in your "Testing" section, but I wasn't sure if you were trying both T1 CSU ACEs or just connecting the one T1 CSU ACE to both ports on the PBX.
The LEDs are split into NETWORK and EQUIPMENT indicators, with the NETWORK being the T1/PRI from the telephone company, and EQUIPMENT being your end equipment (in this case your PBX). The LOS is a "loss of signal" indicating the CSU is not receiving a T1 signal from the PBX.
If both T1 CSU ACEs show EQUIP LOS when connected to the LD port of the PBX then the problem is the connection from the PBX LD port to the T1 CSU ACE's equipment (CPE) port. The PBX LD port should also be indicating an LOS condition. If this is the case, then you can try a T1 cross-over cable (https://supportforums.adtran.com/docs/DOC-4103) in case the Tx and Rx pairs are reversed.
Hope this helps,
Thank you for your assistance and I will remember this and use you again.