Oh: odd if you ask me since Edwards products with “Edwards GS” on the outside are a thing (including “100-series” devices).
Edwards bought a company called “FAST, Inc.”, or “Fire Alarm & Systems Technology, Inc”, in 1992, which is where EST came from: General Signal however bought Edwards all the way back in 1962. SPX Corporation then acquired General Signal (& thus Edwards) in 1998 (& then Edwards changed hands again several times after that: first GE, then UTC, & now finally Carrier Global (well, until Carrier sells their fire division to someone else that is).