EST3 unprogrammed device datacard trouble

Does anyone know what the EST3 “unprogrammed device datacard” trouble is? It pops up sometimes on the annunciator at my high school and I want to know what it means, if anyone knows.

Sounds like the system has a device/module that it’s reading, but the location/address wasn’t put in.

Does it have to do with the NACs or something with the SLCs?