Decode legacy fire panel trouble and supervisory messages with common code guides, grounding checks, loop isolation

https://cesarixwh332.tearosediner.net/choosing-the-right-fire-safety-partner-for-large-multi-family-spaces-in-new-haven

Decode legacy fire panel trouble and supervisory messages with common code guides, grounding checks, loop isolation, and testing steps that restore reliability without premature replacements.