We are trying to replace a external adtran (t3su) and HSSI Card with a NM T3 card (with builtin T3SU). When we move the circuit over to NM T3 card from external adtran for some reason it does not see the circuit and interface and controller stays down down.
We have verified all the settings with carrier several time CRC32, LINECODE, CLOCK SOURCE, SCRAMBLING, DSU MODE etc. and all these settings are correct. The weird thing is that circuit is working fine with external ADTRAN (T3SU). We are already working with Cisco to look into this issue. We are having this issue in more than one sites so its very less likely possible that its hardware issue. Cisco is suggesting to use the attenuators , as per them may be signal strength is too high or too low for the NM T3 card that its showing down down. But incase of attenuation issue you would mostly see LCV Errors , in our case error counter is zero, but funny thing is all LCDs are green.
I would appreciate if anyone can advise something in this scenario. Please let me know if anyone has seen or heard of this type of issue before.