The logo has nothing to do with whether the siren has an AC-only, DC-only, or AC/DC configuration.
The logo simply tells us how old the siren is:
- The blue rectangular logo was used from the 90s to the mid-2000s.
- The circular logo with the three arrows was used from the late-2000s to the mid-2010s.
- The white rectangular logo was used from the mid-2010s to present day.
All Tempest sirens use DC motors. The different configurations are simply how the siren gets its DC power:
- The AC-only config uses an AC-to-DC rectifier; it has no batteries and cannot function without AC line power.
- The DC-only config uses batteries paired with a battery charger. It cannot function without batteries.
- The AC/DC config has everything- rectifier, batteries, battery charger. It runs on AC line power until there is a power outage/failure, which it then switches over to battery power.