Federal Signal EOWS

The **EOWS (Electronic Outdoor Warning Siren)** series, also known as the **SiraTone** series, was a series of electronic sirens that were produced by Federal Signal over a span of 20 years, coming in both omnidirectional and rotational models. It was Federal Signal's first attempt at making an electronic siren, and while they had some teething issues, the series proved to be a very popular option, competing with Whelen's WS-2000, WS-3000, and WPS-4000 sirens, and later ACA's Alertronic sirens.

## History

The EOWS series began in 1981, when the Zimmer nuclear plant was looking for a system of electronic sirens with voice capabilities, and Federal won the bid. Lacking any electronic siren options, Federal produced the very first EOWS sirens, which were then known as EOWS\*1212 sirens. These early units were plagued with issues, such as failing drivers and faulty controllers. When the Zimmer nuclear plant fell through and became coal-fired, the 30 sirens that were made were sent to the surrounding communities. Several of these prototype units are still in service, many running on newer controllers. After the Zimmer units were completed, Federal decided to make an entire series of electronic sirens, which are as follows:

### EOWS\*115

    The **EOWS\*115** is a very simple siren, with a tall hexagonal fiberglass housing containing 12 100 W speaker drivers, as well as the wiring. A small rainshield on top helps protect the electronics. The siren uses 12 rectangular fiberglass Atlas CJ-44 horns, which aren't very efficient. Because of this, the EOWS\*115 has the lowest performance of the EOWS series, being only 113 dB at 100 ft. However, it also costed the least, and even after the EOWS\*1212 was introduced, the 115 continued to be sold. The first model in the EOWS series, these are almost identical to the Zimmer units, with the only difference being the improved SiraTone controller which fixed many of the issues the Zimmer units had.

### EOWS\*408

    The **EOWS\*408** is a rotational siren that was introduced sometime after 1981, alongside the 812. The EOWS\*408 was a compact, small rotating electronic siren that made use of 8 100 W speaker drivers, with two drivers per horn. The EOWS\*408 only used 4 horns and used University Sound DR-42 aluminum speakers which offered better performance than the Atlas speakers. Originally, the speakers were recessed into the siren's housing, but due to manufacturing troubles the speakers were changed to be bolted directly onto the housing in 1983. The EOWS\*408 utilized a Dynapac K-25 rotator along with collector rings to allow the siren unit to rotate 360 degrees. It was introduced as the cheaper, less powerful option compared to the larger EOWS\*812 and reached 119 dB at 100 ft.

### EOWS\*812

    The **EOWS\*812** was the other rotational option introduced in 1981, with twice the speakers of the EOWS\*408. The EOWS\*812 is the tallest siren in the series, using the exact same rotator mechanism and horns from the EOWS\*408. The four speakers in the middle of the siren have 2 100 W drivers each, while the top and bottom rows of horns have only a single 100 W speaker driver per horn for a total of 12 drivers. This siren wasn't very economical, but its performance was great, outputting 124 dB at 100 ft. Like the EOWS\*408, the EOWS\*812 was redesigned in 1983, with its speakers now being bolted directly onto the housing.

### EOWS\*M12

    The **EOWS\*M12** was a vehicular siren intended for short-range notification, and not much is known about it. It was meant for use as a mobile public notification system, to be mounted to the roof of a police car or van at large events. These were built with 4 Atlas CJ-44 horns (the same used on the EOWS\*115) attached to a small housing with 4 small drivers. These were quite large and took up nearly the whole roof of the car. The only known sound rating is 123 dB at 10 ft.

In 1984, the EOWS\*408 and EOWS\*812 were discontinued and replaced with the EOWS\*612 and EOWS\*1212, which offered superior performance. The EOWS\*115 would continue to be sold as a more cost-effective option, alongside the EOWS\*1212 until it was discontinued in 1988. The EOWS\*M12 would likely be discontinued around the same time.

### EOWS\*1212

The **EOWS\*1212** was introduced in 1984 and was designed as a higher-performance version of the EOWS\*115. The EOWS\*1212 is entirely identical to the EOWS\*115, except for the speakers used. The EOWS\*1212 uses the same University Sound DR-42 speakers that the EOWS\*408, 812, and 612 use, instead of the Atlas speakers the 115 used. Because of this, the EOWS\*1212 offered better performance, reaching 115 dB at 100 ft. While it was better in performance than the EOWS\*115, it was also more expensive. Because of this, the EOWS\*115 remained in production alongside the EOWS\*1212 as a cheaper, lower-performing option. The EOWS\*1212 would be discontinued in 1990, being directly replaced by Federal Signal's Modulator which was released the same year.

### EOWS\*612

    The **EOWS\*612** is the most popular option in the EOWS series, as well as its longest-lived. The EOWS\*612 was introduced in 1984 alongside the EOWS\*1212 to replace the EOWS\*408 and 812. The EOWS\*612 matched the sound output of the EOWS\*812 while being nearly as compact as the EOWS\*408, leading it to being the best of both worlds. The EOWS\*612 uses six University Sound speakers, with 2 100 W drivers per speaker for a total of 12. Because of this, it was able to output 124 dB at 100 ft, the same as the EOWS\*812.

The series would be discontinued in 1990, being directly replaced by Federal Signal's Modulator which was released the same year. Federal lacked any other option for a rotating siren, which was still in demand, so it was decided that the EOWS\*612 would still be sold. The EOWS\*612 was compatible with the Modulator's controllers, allowing it to be kept modernized. The siren would be removed from Federal's site in 2001 but was available on special order until it was finally discontinued in 2007, when University Sounds' parent company, Altec Lansing, nearly went bankrupt and shut down University Sounds, leaving Federal with no supplier for the speakers. Despite this, existing EOWS\*612 units are still compatible with modern controllers, both from Federal and other companies' controllers, and because of this many units are still in service long past their production.

The EOWS series is highly compatible with any modern electronic siren controller, such as Federal's MC, MCP, and UltraVoice controllers, as well as Whelen's analog and digital controllers and ACA/ASC's controllers. Because of this, EOWS sirens can be kept in service long after their controllers begin to fail. This is why despite many newer electronic sirens being available, some cities still keep their old EOWS systems. Today, EOWS sirens are somewhat uncommon due to their age, but can still be found across North America.

## References

1. ↑ (Electronic Outdoor Warning Siren)
2. ↑ (also known as the SiraTone series)