2 Replies Latest reply on Mar 7, 2013 3:58 PM by gsr99

    T1 CSU ACE

    gsr99 New Member

      T1 CSU ACE 1st Gen. (part #1200022L2)


      Problem: CSU equip. los indicator light on for PBX LD PRI only. CSU for local PRI working ok.


      Equipment: T1 line to smart jack card rack

                           Adtran CSU ACE 1st Gen.

                           Avaya 412 PBX w/A&B PRI slots

                           Cat 5e W/RJ48c (10ft)

                           APC UPS power supply


      Testing:   1. Replaced cable (no change)

                       2. Moved CSU local CPE cable to CSU LD CPE port (equip. los indicator light off)

                       3. Moved CSU LD CPE cable to CSU local CPE port (equip. los indicator light on)

                       4. Contacted local provider to test circuits (all clear point to point)

                       5. Shunt CPE port on LD CSU (equip. los indicator light off)


      Note: PBX system working ok till line work out at street was done.


      Configuration provided by provider:

      LD circuit config.

      Switch Type = 4ESS
      NPT = APN
      SubScribedSvcs = MEG8,SDN,LOCO
      Z Frame Format = ESF
      Z Line Code = B8ZS

        • Re: T1 CSU ACE
          patrick Employee

          Thank you for using the ADTRAN Support Forums.


          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,