Douglas Krantz - Technical Writer - Describing How It Works

Can I Replace One Manufacturer's Panel with Another Manufacturer's Panel?

By Douglas Krantz | Maintenance

Can I Replace One Manufacturer's Panel with Another Manufacturer's Panel?

Can I Replace One Manufacturer's Panel with Another Manufacturer's Panel?

Greetings Douglas,

Is it possible to replace a Simplex panel with a Honeywell panel?

I am sure there will be issues, but is it possible to replace some or most of the Simplex detectors and other modules with Honeywell modules?

Thank You, AN


People talk about compatibility requirements in terms of "Compatibility is required, so we will make sure that the system is 'Compatible'". However, being compatible isn't really an issue demanded by the National Fire Protection Association (NFPA); being compatible isn't really an issue keeping the fire marshal happy; being compatible isn't really an issue keeping lawyers employed. These are all secondary issues.

The primary issue with being compatible is "Do different parts of the system even work together - at all?"


All fire alarm manufacturers are proprietary. The first manufacture is afraid that if a second manufacturer has something connected to the first manufacturer's system, and the second manufacture's equipment fails, the first manufacturer, even though they had nothing to do with it, will also be held liable.

To keep the systems proprietary, the protocol (digital language), and often even the voltages used are kept secret, or at least hard to work with by anyone else.

Panels and Devices

Addressable devices and control panels are designed to work together as a package. Mixing one manufacturer's devices and another manufacturer's addressable devices will never work. It's like saying "Alarm" in the Swahili and expecting someone who only knows Norwegian to understand it. Simplex and Honeywell are not compatible.

A complete changeover is required, including detectors, input modules, output modules, and anything else addressable, or nothing will work.

Horns and Strobes

Horns have to be synchronized or the sound gets confusing. Strobes have to by synchronized, or epileptic seizures may result. The method of synchronization used by Honeywell, and the method of synchronization used by Simplex will not work with mixed and matched devices. Probably, all horns and strobes have to be replaced, along with any synchronization equipment.

Be careful of the wiring. If the Simplex system is using a 29-volt regulated system for powering the horns and strobes, you will have to use a 29-volt regulated system for powering the new horns and strobes . . . or rewire the building.

The problem with the wiring is the 29-volt regulated NAC wiring systems are just fine when planned out with 29-volt regulated power supplies, but the wires are totally inadequate to handle horns and strobes when using the 24-volt nominal power supplies used in most fire alarm NAC wiring systems.


Unless the speakers are addressable, the speakers have a good chance of working, but I wouldn't count on it. Consider replacing the speakers.

If the speakers are addressable, the Simplex speakers will not work with any other system. Even the wiring has to be carefully examined before replacing the speakers with any other system speakers.

Technical Support

Talk to the Honeywell technical support team. Ask them about compatibility. Before calling, though, get some information.
  • Find out about the Signaling Line Circuit (SLC). What kind of wire was used with the Simplex System, size of the wire, and whether the wires are shielded. Even the total length of the wire needs to be taken into account when talking to technical support.

  • Find out about the power used for the horns and strobes, whether it's 29-volts regulated or 24-volts nominal.

  • Find out about the speakers, and whether they are addressable. Get the Simplex model numbers on the speakers, and on the power supplies.

The technical support team will give you lots of information.


The bottom line regarding compatibility is if parts of the fire alarm system aren't compatible, there's a good chance the incompatible parts won't work together reliably, if at all.

Douglas Krantz
Life Safety
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