I have 12 switches and 16 blocks controlled by ASCs and block controllers. Suddenly they all stopped working. The other twelve switches controlled by SCIIs work fine. The leds on all units are fast blinking constantly. The manuals say that a fast blink indicates that the controller is receiving a command for another device. Since all units are flashing The "command" must be an error.
Tried swapping out the command base for my spare. No change.
Opened up the DB9 connector, checked continuity on both leads. No problem found.
Removed all batteries from CAB 1s on the off chance that a stuck key was sending a random signal to the base. No change.
Anybody have any ideas?