I've been working on a site that has 7 T1s going through a Canoga Perkins 3240S MUX.

The line coding we have our equipment set up for is B8ZS. One of the MUXs went down along with the T1s. They were down for s few days before the MUX was replaced. When we hooked up a test set to the demarc where the 7 T1s come in, the tester read AMI. I was told that since the site on the distant end was down and there were no users trying to transmit data, that B8ZS would not be present and the tester would see all 0's (AMI). When we were on the phone with the provider and they were doing testing with us our testers (Easy Tester II) B8ZS LED would flicker. Is that normal? Is B8ZS dependent on data on the circuit? So if there was no data it would be all 0's or AMI. Also we noticed that when we had a loop at the far end we would see a solid light on the testers B8ZS LED. Is that because the tester was sending a constant signal for B8ZS coding?

Thanks