Absolutely nothing at all on the console? Not even gibberish on initial boot? Have you verified your terminal settings and connections?
If the console connection is indeed good, this sounds like bad hardware or at least something that you aren't going to be able to fix without getting Adtran support involved.
Have you checked the power source? Possibly low or incorrect voltage?
If no network cables are plugged in and they are doing that definitely a power source or hardware issue because it is likely stuck in a reboot cycle. If network cables are plugged in and all the lights blinking at the same time every second it could also be a network loop and it is causing the CPU and or memory to overload, unplug all network cables, reboot the units and see if problem goes away. If problem still continues most likely power issue or hardware failure.