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SiraTone Controller.png
Company Federal Signal Corporation
Produced July 16, 1981[1]-1992?
Type Electronic Siren Controller
Succeeded by MC

The SiraTone was the first electronic siren controller produced by Federal Signal Corporation. It can be found on the EOWS, Modulator, and DSA series of sirens. SiraTone was an analog based dual tone controller that was designed to mimic the characteristics of Thunderbolt 1003. It first debuted on July 16, 1981 with sale of the first units. It's a mystery as to whom received the first models between Zimmer Nuclear and Pilgrim Nuclear. These controllers produced up to 1200W of power to the speaker array and pulled 5 Amps of current. These units ran on 24VDC from 2 deep-cycle 12V batteries and could be charged on automatic 120VAC or 240VAC battery chargers or from a solar panel.



SiraTone came with 7 signals, 6 standard and 1 optional AUXILIARY (AUX) signal. The 6 standard tones were: Steady, Alternating Steady, Pulsed Steady, Wail, Alternating Wail, and Pulsed Wail. The AUX signal was an optional tone module that could be chosen during purchase, or purchased when signalling needs changed. The AUX tone module could be ordered with one of many tones: Yelp, Yeow, Slow Whoop, Temporal Slow Whoop, Bell, Gradual Horn, Westminster Chimes (16 step), and Westminster Chimes (8 Step). These tone modules are identical to ones used in SelecTone, and can be ordered today in the form of the UTM or Universal Tone Module[2].

Local and Remote Live PA

SiraTone came standard with a local Live PA function. The controller shipped with a microphone that connected to the 6.3mm audio jack on the control module. The controller will automatically stop all operations whenever Live PA is activated and will begin broadcasting immediately. Remote PA is an optional radio broadcasting system that allows messages to be broadcasted through the speaker array from a base station.

Radio Control

SiraTone like many other Federal Signal products was available with radio activation methods. It utilized the SiraTrol radio system. It's possible that it was paired with the SC radio found on Modulator, DSA, and late EOWS*612 arrays.

Home/Remote Control Positioning (EOWS*408, 612, and 812 only)

This feature allows you to set 4 zoning positions for the rotational speaker array to face. Radio or land-line activation can position the array in any zone to broadcast an area announcement in one direction. The standard automatic incrementing function will move the speaker array to the next zone after a transmission is completed. Late model 612 arrays are equipped with a position sensor that tells the controller where the array is facing. The sensor is used to position the array rather than the built in increment timer for much more precise array positioning.

Quiet Test

Quiet Test performs diagnostics on the operational status of the unit. Signal A and B, amplifiers, speakers, batteries, battery chargers, and rotator (if present) will be monitored. The status is displayed on the LEDs found on the Quiet Test board and/or other systems interfaced to the Quiet Test board.


This is 2-way communication system that monitors the unit's operation and can report back to the base station when an action is performed or the base station polls the system for operational status.


The SiraTone was housed in a NEMA 4 cabinet, while the batteries were housed in a NEMA 3R cabinet. Both enclosures were powder coated steel. The later C/BSB controller could be found in powder coated steel, stainless steel, or aluminum with a NEMA 3R or NEMA 4 battery enclosure.


The amplifiers used in SiraTone were built in-house by Federal Signal and produced 200W of power each. Each amplifier powered two 100W speaker drivers.


SiraTone C/B

SiraTone C/B was the 6 amplifier, 1200W variant of the SiraTone. This model was paired with EOWS*115, EOWS*1212, EOWS*612, and EOWS*812.

SiraTone C/BSB

SiraTone C/B Series-B is the revised model of the original C/B with component upgrades on the control module to improve stability and reliability. In addition to that, changes were made to the controller layout and upgrades made to the power supply/charger unit. A low voltage cut-off module was also added to shut the controller down if the batteries became too weak to maintain proper usage. This was done to prevent damage to the control module. This controller can be found paired with EOWS*1212, EOWS*115, EOWS*612, Modulator, and DSA.

SiraTone C/B4

SiraTone C/B4 is identical to C/B, but only has 4 amplifiers for 800W of power. It was used to power the EOWS*408 array.

SiraTone C/M12

SiraTone C/M12 is the variant used for EOWS*M12. Specifics are unknown.