Siren Controller

Siren controller systems for audible and visual warning equipment

How does a siren controller unit operate?

A siren controller unit activates the selected tone in response to an operator command and sends the amplified signal to a compatible speaker. Operation may be performed using push buttons, a rotary selector, the vehicle horn control, a handheld microphone or a separate control panel. The available models include versions with 6 selectable tone patterns and units with 29 siren tones. Certain controllers also support manual tone activation, air horn operation, hands-free control and horn ring transfer mode.

Electronic siren and audible warning control

The electronic siren controller range includes models with rated output powers of 100 W and 200 W. The Strobos HSP is a 100 W unit, while the HSP2 provides 200 W and controls two 100 W speakers. In the A500 series, the siren signal frequency range is 500-2000 Hz, while the PA audio frequency range is 300-10000 Hz. The audible warning controller must therefore be selected according to its rated output and the permitted speaker configuration.

Which supply voltage is suitable for the warning system?

The electrical system voltage of the vehicle must be compatible with the controller. The available products include separate 12 V and 24 V Strobos units, EA600 amplifiers operating from 12-24 Vdc, A500 models with a 10-30 Vdc input range, and SW830 switching systems designed for 10-24 Vdc supply voltage. Using a controller or lighting device with an unsuitable voltage may damage the equipment and the electrical system of the vehicle.

Control panels for 12 V and 24 V electrical systems

Dedicated 12 V and 24 V control panels are not interchangeable. The wider input ranges of the EA600 and A500 series allow installation in different vehicle electrical systems, but fuse ratings and conductor sizes must be selected according to the current requirements of the specific model.

How should the speaker be matched to the emergency warning system?

The impedance and rated power of the emergency warning system speaker directly determine which controller can be used. The EA600 supports one 100 W speaker with an impedance of 11 ohms or 8 ohms, or two series-connected 50 W speakers with an impedance of 4 ohms each. The A501 supports one 100 W, 11 ohm speaker. The A503 supports one 100 W, 8 ohm speaker or two series-connected 50 W, 4 ohm speakers. Strobos units may be connected to speakers with an impedance of 6-11 ohms.

Combined audible and visual warning control panel

A combined control panel places audible and visual warning functions on a shared operator interface. The Strobos HSP and HSP2 versions provide 5 high-current channels for warning and auxiliary lighting. The A500 system includes 3 level outputs rated at 8 A each and 6 AUX outputs rated at 0.2 A each. The combined load of the three level outputs must not exceed 25 A. The eight switches of the SW830 control three 10 A outputs and five 0.2 A outputs. Each switch can be programmed for ON/OFF or momentary operation.

Which PA and radio functions are available?

Models equipped with a PA function transmit speech from a microphone through the siren speaker. The EA600 supports an optional push-to-talk microphone, adjustable PA volume and radio rebroadcast. Its Record-n-Play function can record and play back a message lasting up to 30 seconds. Strobos controllers include a built-in microphone, a radio connection and support for an external audio source.

Warning signal control in day and night modes

Warning signal control varies by model. Strobos units provide a separate night mode, while the EA600 includes day and reduced-output night volume settings. The illuminated controls of the A500 assist with button identification.

What must be checked before installation?

The siren controller must be installed inside the vehicle in a location protected from moisture and provided with sufficient airflow. The control panel must remain accessible to the operator, but it must not be installed within an airbag deployment area or in a position that interferes with vehicle operation. Wiring must be completed by a person with appropriate technical knowledge, using the specified fuses, conductor sizes and grounding points.

• Vehicle supply voltage and polarity.
• Rated output power of the siren amplifier.
• Speaker power, impedance and wiring configuration.
• Number and permitted load of the lighting outputs.
• Requirement for a PA microphone, radio input or external control.
• Installation location, ventilation, cable routing and fuse protection.

Industrial signalling equipment or emergency vehicle warning system?

The described siren controllers are intended for the audible and visual warning systems of specialist vehicles. The product range includes solutions designed for police, fire service, ambulance and military vehicles.

Certifications and regulated use

The products include ECE R10 or E20 R10 electromagnetic compatibility compliance. Certain SoundOff Signal configurations, when used with the specified speaker, are associated with SAE J1849, UTAC or CA Title 13 requirements. The A500 series also includes versions with CISPR25 Class 1 classification. The use of emergency audible and visual warning equipment on public roads is subject to authorisation.

Advantages and limitations of siren controllers

Advantages:

• Audible warning, lighting control, PA operation and radio audio can be integrated into one control system.
• Models are available for 12 V and 24 V systems with rated outputs of 100 W and 200 W.
• Several models use diagnostic LEDs to indicate voltage faults, overcurrent, overheating or speaker faults.

Limitations:

• Controller and speaker impedance cannot be selected independently.
• The individual and combined load limits of the lighting outputs must be observed.
• The equipment requires installation in a location protected from moisture, and its use on public roads may require authorisation.

Frequently asked questions about siren controllers

• What is the difference between a 100 W and a 200 W siren controller?
  The number, rated power, impedance and wiring configuration of the connected speakers are determined by the controller model and its rated output.
• Can a 12 V controller be used in a 24 V vehicle?
  No, when the controller is designed exclusively for 12 V operation. A model with a 12-24 Vdc or 10-30 Vdc input range is required for wider voltage compatibility.
• Why is speaker impedance important?
  The output stage of the controller is designed for a specified speaker impedance and wiring configuration.
• Can the warning lights be controlled from the same panel?
  Yes. Models designed for combined operation provide high-current and low-current outputs for warning and auxiliary lighting.
• What is the PA function used for?
  The PA microphone transmits speech through the siren speaker. Certain models can also rebroadcast radio audio or play a recorded message.
• Where can a siren controller be installed?
  It must be installed inside the vehicle in a dry, ventilated location outside all airbag deployment areas.

Which siren controller is suitable for the system?

We recommend selecting a siren controller whose supply voltage matches the vehicle electrical system, whose output power and supported impedance correspond to the connected speakers, and whose outputs cover all required warning lights. When PA or radio functions are required, the necessary audio inputs must also be verified. The final selection must also consider the installation location, wiring, fuse protection, certification and authorised field of use.