1. What do ZCS and B8ZS have in common, and how do these signals work? 5. What, if anything, is the difference between AMI, ZCS, and B8ZS?
2. What is the correlation between CSU/DSU and AMI, ZCS, and B8ZS? 7. What is a major problem with a digital circuit using ZCS as a keep-alive signal and that signal's carrier using B8ZS signaling?