EOWS Series

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EOWS series
Company Federal Signal Corporation
Produced 1981-2001, 612 available on special order up to August 3, 2007
Type Electronic
Sound output 113-124 dBc at 100 feet
Succeeded by Modulator & DSA
Product sheet

The EOWS series (Electronic Outdoor Warning Siren) was a line of electronic sirens produced by Federal Signal Corporation.

Early Production

Former Zimmer prototype unit still in service on a modern UltraVoice controller.

The EOWS series came to light in 1980 when Federal Signal won a bid for an electronic siren system to be installed at the now coal-fired Zimmer nuclear plant. Federal Signal however did not have an electronic siren line, so this led to a new development they called SiraTone. Federal Signal produced around 30 prototype model EOWS*1212 sirens for the plant system in 1981. You may notice that these sirens look identical to the 115, but they are 1212s as stated by the documentation tied with them. The heads interestingly enough did not have identification badges. The original system of prototype 1212s were later absorbed into surrounding communities after the Zimmer nuclear plant fell through. A few can be found today still in service, however most are on newer controllers. Federal created a very simple, yet effective electronic siren. It was a cluster of 12 speakers consisting of rectangular re-entrant horns made out of fiberglass, sourced from Atlas Sound along with the 100 Watt compression drivers behind them. The frame/enclosure was made custom by Federal Signal themselves.

Further Expansion

After Federal Signal created this new product, they worked out some kinks with the SiraTone controller and expanded upon their electronic line with the introduction of the models 408, 812, and M*12. The 408 and 812 were rotating beam sirens made for better sound concentration and projection, while the M*12 was simply a mobile vehicular siren aimed for public events and such. Despite these new additions, the 1212 was still available as the only omni-directional model they offered. However, they changed the name from 1212 to 115. The reasoning behind the name change is unknown.

For the new rotating arrays, Federal chose a simple design similar to rotating signs of the time and struck a partnership with Dynapac Rotating as their supplier for their rotation mechanisms. These arrays featured Dynapac's K-25 rotator with a quad-brush collector ring assembly allowing the arrays to rotate a full 360° stall free, requiring little to no maintenance. Likewise, Federal also partnered up with University Sound (an Altec Lansing company) as the supplier for the 26" spun aluminum horns used for the EOWS*408 and 812. In early stages, the EOWS*812 and 408 were made in a more "compact" manner with the projection horns recessing into the rear frame. This was very short lived likely due to manufacturing troubles, and was ditched by 1983, with the horns being mounted directly to the frame wall.

Towards the end of 1984, Federal Signal introduced 2 new EOWS products, the 1212 and 612. EOWS*1212 was simply a 115 with the 408 and 812's aluminum horns replacing the original rectangular fiberglass ones on the 115. This was done for a small boost in performance thanks to better sound propagation with the aluminum horns, while also unifying the product line with the existing models. EOWS*612 was a combination of the 408 and 812. It's performance matched the 812 while staying relatively compact like the 408. It also used less materials than the 812, making it much more economical, not to mention easier to handle/manage. With the introduction of said models, came the discontinuation of the 812 and 408. However the 115 stuck around as a cheaper base model EOWS that performed a little worse than the 1212. Discontinuation of the M*12 is unknown.

Late Production and Discontinuation

Smaller 20" variant of the speaker model used on the EOWS*408, 612, 812, and 1212.

Federal Signal continued production of the EOWS*1212, 115 and 612 for a few years, eventually killing off the 115 sometime in 1988. The 90's rolled around and things started to change quite a bit. Federal Signal created a new omni-directional siren named the Modulator in 1990, leading to the demise of the EOWS*1212 the same year. However, Federal Signal kept the 612 in production, likely because it was their only rotating electronic siren at the time, it was efficient and powerful, and people still wanted to purchase them. They kept it up to date, modernizing it with their latest MC controller at the time. The EOWS*612 stuck around for many years into the future. However, Federal Signal removed it from their public websites in 2001 and only offered it as a special order model from 2001 up into 2007, with sales ending completely that year with their last model selling on August 3rd, 2007. Federal Signal unfortunately had to discontinue production on the EOWS*612 because they could no longer get speakers for them. Altec Lansing almost went bankrupt, meaning they had to do major budget cuts. To cut their losses, they killed off their University Sound branch, leaving Federal with no source for speakers.

Modern Use

All EOWS units are fairly simplistic electronic sirens, and are easy to update with modern hardware. Many units still in service are on the latest UltraVoice controller from Federal Signal. Many are on older Federal controllers, like the MC and MCP. Some units are even on third party controllers like ones by American Signal Corporation as well as Whelen Engineering. The units were originally manufactured with simple common components, meaning they were easy to repair if needed.

While the 612 was still in production, it received upgrades from Federal Signal with their newer MC controller, then the MCP controller, and later their UV controller. Federal Signal still supports EOWS*612 too. The UltraVoice controller openly states it's compatibility with the 612 in its documentation, earlier documentation stated it's compatibility with the 1212 as well. However, UV isn't limited to just the 612 and 1212. Any model EOWS siren is fully compatible with the UV. A few EOWS*408 units in Massachusetts were fitted with UltraVoice controllers in the early 2000s. Unfortunately these units were replaced by Modulator 5020s in the mid-2000s.


There were a total of 6 mainstream models in the series:

Model Image Output Drivers Notes
EOWS*115 EOWS*115 Official.jpeg 113 dBc 12 (1 per horn)
The earliest model in the series. Uncommon.
EOWS*408 EOWS*408.png 119 dBc 8 (2 per horn)
The smallest rotating siren in the series. Rather uncommon.
EOWS*612 EOWS*612 Official.jpeg 124 dBc 12 (2 per horn)
The most popular model. Many active examples can still be found today.
EOWS*812 EOWS*812.png 124 dBc 12 (2 per horn for middle 4 horns, and 1 per horn for top and bottom 2 horns)
The largest siren in the series. Rather uncommon.
EOWS*1212 EOWS*1212 Official.jpeg 115 dBc 12 (1 per horn)
The successor to the 115.
EOWS*M12 EOWS*M12 Official.jpeg 123 dBc 4 (1 per horn)
Vehicular model. Decibel rating was measured at ten feet.[1]









EOWS812 Manual.jpg



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