Cable Toner Kit Doubles as Fire Speaker Test

Play a Tone Through Your Fire Alarm Speakers with a Toner

A cable toner kit can prove to be a very useful tool in the fire alarm system installation and service business. If you do not know, a cable toner is a battery operated device that places a tone across cables assisting in location and verification. You can simply connect the toner to a pair of wires and then move between junction points with the provided wand looking for the tone. Here is a little trick to help verify your fire alarm voice evacuation speakers are connected correctly.

Of course it is highly recommended to test out your fire alarm speaker circuit with a multi-meter before connecting to your amplifiers. With a multi-meter, you can test for reverse polarity (with the diode check), ground faults, shorts and continuity with the resistance setting and finally check for AC inductance with the AC voltage setting. Once you have verified all is good on your fire alarm speaker circuit we can move on to the cable toner test. I have included a simple video to show the connections and the tone you should receive at all of the speakers connected to the fire alarm circuit. Make sure to turn the cable toner to the "TONE" setting and connect it to the circuit. Red to red and black to black. This will allow the cable toner to produce a tone across the fire alarm speaker circuit and play it through the actual fire alarm speaker appliances. Once this step is completed, walk around the site and verify that you have a fire alarm sound or tone on all of the speakers on the circuit.

Why Use a Cable Toner to Test Fire Alarm Speaker Circuits?

Using a toner on a fire alarm speaker circuit provides a quick, field-proven way to verify:

• Speaker circuit continuity

• Correct speaker wiring and polarity

• That all speakers on the circuit are connected

• No open circuits between junction points

This method is especially helpful on voice evacuation systems, where identifying missed or incorrectly landed speakers early can save significant commissioning time.

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Verify the Fire Alarm Speaker Circuit Before Using a Toner

Before connecting a cable toner to any fire alarm voice evacuation circuit, it is strongly recommended to test the circuit using a multimeter. This helps protect amplifiers and ensures code-compliant wiring.

Using a multimeter, verify the following:

• Polarity using the diode test function

• Ground faults

• Shorts or opens using resistance (ohms)

• AC inductance or induced voltage using the AC voltage setting

Once the speaker circuit has passed all electrical tests and is confirmed safe, you can proceed with toner testing.

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How to Play a Tone Through Fire Alarm Speakers

To play a tone through fire alarm speakers using a cable toner, follow these steps:

1. Set the cable toner to the TONE mode

2. Connect the toner leads to the speaker circuit

   • Red lead to positive

   • Black lead to negative

3. Ensure the circuit is disconnected from the amplifier

4. Activate the toner

When connected correctly, the toner will place an audible signal onto the speaker circuit, causing the tone to be played through each fire alarm speaker appliance on that circuit.

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Walk the Site and Verify Speaker Operation

After activating the cable toner:

• Walk the site and listen for the tone at each speaker

• Confirm that all speakers on the circuit produce sound

• Identify any missing, silent, or miswired speakers

If a speaker does not produce a tone, it typically indicates an open circuit, wiring error, or incorrect termination that can be corrected before final system commissioning.

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Why This Method Works for Voice Evacuation Systems

Using a cable toner to play a tone through fire alarm speakers is a simple but effective verification technique for voice evacuation systems. It provides confidence that the speaker circuit is intact and properly wired before amplifiers, digital audio, and voice messages are introduced.

This approach helps reduce troubleshooting during final testing and supports a smoother inspection and acceptance process.

Reading Reverse Polarity with a Meter

Do you know how to Use a Multi Meter to Locate a Fire Alarm Device or Appliance that has been connected with reverse polarity?

If not this article will explain how to set the multi meter up as well as how to properly break down fire alarm circuits to locate an initiating device and or notification appliance that has been connected with reverse polarity.

Real quick we will start with the basics.  "What is polarity?"  Polarity in electrical circuits is known as "Positive" and "Negative".  In DC (Direct Current) circuits one pole is always positive (typically marked with a + or red) and the other is always negative (typically marked with - or black).  Note that electrons within a DC circuit only flow in one direction.

This is where a lot of people become confused.  There are two common notations of flow for DC circuits. See below:

#1 is the Conventional Flow Notation.  This notation is based on Benjamin Franklin's conjecture regarding the flow direction of charge.  This notation shows charge flow moving from the Positive Pole of a DC circuit to the Negative Pole.  This is the notation that is most commonly used my engineers and is technically incorrect.

#2 is the Electron Flow Notation.  This is the true notation of charge flow as it shows the actual motion of the electrons in a DC circuit.  Note that this notation shows the charge flow moving from the Negative Pole to the Positive Pole. 

Now that we have covered how a charge or current flows through a circuit, it is important to understand how a diode works and how it can allow or block this flow from occurring.

Definition of a DIODE: A semiconductor device with two terminals, typically allowing the flow of current in one direction only.  This direction of current flow moves from the ANODE side through the CATHODE side of the DIODE.  An easy way to remember this is a DIODE allows current to flow in the direction of the arrow within the symbol.

Here is the electrical symbol for a DIODE:

Below are two diagrams that depict the same image however they show the current flowing in opposite directions (conventional vs. electron flow notation).  Notice that even though they both have a diode facing in the same direction the lamp is still illuminated.  "Why is this?"  I thought that a diode only allows current to flow in one direction and that a DC circuit only flows in one direction.  "This would make it impossible to illuminate the lamp in both scenarios, right?"

Conventional Flow Notation with DIODE

Electron Flow Notation with DIODE

         
This is correct.  However the symbol for a DIODE has never been updated to match the Electron Flow Notation.  Therefor the DIODE is always shown with the "Line" or Cathode side pointing towards the positive flow based on the Conventional Flow Notation.  Note that if we were to update the DIODE symbol and show the arrow facing the opposite direction, the diagram based on the Electron Flow Notation would make more sense.

Now on to the point of this article.  "How do I use this information regarding current flow and diodes to locate a fire alarm device or notification appliance that has been connected with reverse polarity?"

A fire alarm initiating device or notification appliance that is polarity sensitive meaning it must be connected with the correct input (positive/negative) will have an internal DIODE to restrict the current flow in one direction as stated above.  We can use the diode setting on our Multi Meter to locate any section of a fire alarm circuit that has been connected backwards or with Reverse Polarity.

How it works:  When you select the DIODE setting your Multi Meter will force a small amount of current through the DIODE and measures the voltage drop across your Multi meter test leads.

Forward Bias Diodes:  If you have the Positive test lead connected to the Anode side and the Negative test lead connected to the Cathode side of the DIODE, your Multi Meter should display something close to 0.548 Volts.

Reverse Bias Diodes:  If you have the Positive test lead connected to the Cathode side and the Negative test lead connected to the Anode side of the DIODE, your Multi Meter should display OL (Open Line).

I suggest testing a single device/appliance on a specific circuit prior to searching for reverse polarity on a fire alarm run. This can be accomplished by using a spare or by taking down a device on a circuit you need to test.  Once you have the fire alarm device or notification appliance removed, place your positive (red) multi meter test lead on the positive terminal of the equipment and the negative (black) multi meter test lead on the negative terminal of the equipment.  If your multi meter displays 0.548 Volts then you have a circuit with Forward Bias Diodes.  If your multi meter displays OL then your circuits has Reverse Bias Diodes.

Here is the key to the puzzle.  If you test the wire in your circuit and your meter displays a dead short (0.000 and typically sounds a steady beep) then your circuit has one or more devices wired backwards.  This is known since diodes in Forward and Reverse bias positions would allow the current in your circuit to travel in both directions ultimately resulting in a dead short.

Now that you know which orientation your circuit's diodes face, you can start breaking down the circuit in halves.  Each time you cut the circuit in half, read the wires in both directions paying attention to multi meter's display looking for either 0.548 V, OL or a dead short.

This easy to use Multi Meter trick will help you eliminate very time consuming labor when troubleshooting fire alarm circuits.

How to Use a Multi-Meter for Fire Alarm

Multi Meter Basics

One of the most important tools a fire alarm technician posses is the digital voltmeter or digital multi meter.  This article will explain the different settings and how they can help you track down important circuit information such as end of line resistance values, current draw, reverse polarity, dead shorts, ground faults, AC inductance and capacitance.

I cannot stress enough the importance of purchasing a quality voltmeter or multi meter.  For the purpose of the this article I will be utilizing a Fluke 117.  This is a high end meter that won't break the bank.  It has all of the key settings including a back-light for dark spaces as well as non-contact voltage detection.  In case you did not catch that last one, it will detect high and low AC voltage just by simply holding the meter close to the source.

You can read more about this powerful true-rms multi meter here.

In this article we will show you how to properly tune the voltmeter or multi meter to the correct settings as well as when to move the test leads depending on what circuit information you are trying to obtain.

Now it is important to explain the different symbols and buttons so that you better understand how to navigate through this information.

Please note that although I am referencing the Fluke 117, these symbols should be close to the same on any multi meter you are using in the field.

Multi Meter Buttons and Functions:

"HOLD" This button will hold the display at the current view for documentation at a later time.  As you may know, the multi meter display may fluctuate from time to time so this button can prove to be useful if you want to lock it in at a particular time.

"MIN/MAX" As stated above the multi meter display will fluctuate between higher to lower readings.  This button can be pressed to either lock in the lowest/minimum or the highest/Maximum reading. Also note that on this meter, there is another selection with this button that will display the average between the minimum and maximum.

"RANGE" This multi meter has both manual and auto-ranging modes.  In auto-range mode the meter will automatically select the range with the best resolution.  In manual mode you must use this button to cycle through the different ranges whether it be for resistance, voltage, current capacitance, etc.

"YELLOW BUTTON" the yellow button on this meter is like a shift key.  It will allow you to select the yellow options located on the rotary wheel.

Below is a list of the most important multi meter modes and what they can be used to test for.  Feel free to click on the separate links to read further on these topics:  Please note the picture below is of a FLUKE 115 which is basically the same as the 117 minus the AUTO-V LoZ and Volt Alert settings.

Selections via Multi meter Rotary Wheel:

"AUTO-V LoZ" Automatically selects ac or dc volts based on the sensed input with a low impedance input.
AC voltage from 0.06 to 600 V.
DC voltage from .001 to 600 V.

AC voltage from 6.0 to 600 mV
DC voltage from 0.1 to 600 mV

Learn More About Reading for Voltage on Fire Alarm Circuits Here.

Ohms from 0.1 ohms to 40 milliohms
Continuity beeper turns on at less than 20 ohms and turns off at greater than 250 ohms.

Learn More About Reading for End of Line Resistance, Ground Faults, Shorts and Continuity on Fire Alarm Circuits Here.

Diode test.  Displays OL (Open Line) above 2.0 V.

Learn More About Reading for Reverse Polarity on Fire Alarm Circuits Here.

Farads from 1 nF to 9999 micro Farads

Learn More About Reading for Capacitance on Fire Alarm Circuits Here.

AC current from 0.1 A to 10 A.
DC current 0.1 A to 10 A.

Learn More About Reading Current on Fire Alarm and Control Circuits Here.

"Volt Alert" Non-contact sensing of ac voltage.

Reading Electrical Current with a Meter

As you may know, fire alarm control equipment has current ratings and limitations.  For example, an addressable relay module from Notifier (FRM-1) has the following current limitations:

3 Amps @ 30 VDC Resistive Non-Coded
2 Amps @ 30 VDC Resistive Coded
.9 Amps @ 125 VAC Resistive Non Coded

This is letting us know that if we need to switch a 30 volt DC (Direct Current) circuit through this relay, we must be below 3 amps (for Non-Coded) and 2 amps for (Coded).

There are two ways to find out if we are below this number.

#1) Read the data sheets and instruction manuals of the equipment that is being powered by this circuit.  These informational sheets should have the current load numbers for your use.  Add this number up by the quantity of equipment to be powered and you should have a number close to reality.  I do not recommend this as you may end up calculating a number lower than actuality therefor jeopardizing the fire alarm relay.

#2) With the proper use of a Multi Meter we can get an exact current reading from any circuit (as long as it is energized).  Now keep in mind that Multi Meters have limitations on the current that can read as well.  For example the Multi Meter we are using for this example has a 10 A fused limit for reading AC/DC current. Read below to find out how to set your Multi Meter up for reading current.

Before we continue please know the difference between a series circuit and a parallel circuit.  In order to measure the load or current of a fire alarm circuit, we must place the Multi Meter test leads in SERIES with the circuit to be read.  This is very important as it is impossible to do otherwise.  Also note that you will need to move the positive test lead to the Amp test lead port as shown in the pictures below:

This picture shows the Fluke 117 Multi Meter with the test leads in the normal position to meter for voltage, resistance, capacitance, etc.

This pictures shows the Fluke 117 Multi Meter with the positive test lead moved over to the Amp port.  This is mandatory when checking a fire alarm circuit for current.










Now as we stated above you need to place the Multi Meter test leads in series with the circuit being read. For example:  If you have a relay with one leg landed on the C (Common) terminal and the other leg landed on the NC (Normally Closed) terminal your circuit is complete and the equipment being controlled should be functional.  If you pull the wire leg off of the Common terminal, the equipment should stop.

Before we connect the Multi Meter to the circuit we need to insure we have the meter on the correct setting. Be aware if you are reading an AC or DC circuit and select the appropriate setting as noted in our previous article discussing Multi Meter basics.

Now with the wire disconnected from the Common terminal, land your negative (black) test lead on the Multi Meter to that same terminal on the relay.  Now we need to complete the circuit to get an accurate current reading.  Land the positive (red) test lead on the multi meter to the wire leg you disconnected from the Common terminal.  If done correctly the equipment should power back up and your Multi Meter will display the total current of that circuit.

Below are a couple of pictures showing how the Multi Meter test leads should be connected to the circuit to properly read for current.  Please note that the circuit used in these pictures is an SLC connected to a Notifier NFS2-3030 branching off to five FCM-1 addressable control modules.

SLC Connection on Terminal Strip

SLC On Terminal Strip with Negative Conductor Disconnected for Current Reading

Meter probes to make continuity between terminal and disconnected wire

If this is not something you feel comfortable with, then Fluke has you covered.  Below is a picture of a current reading clamp that they make for their Multi Meters.  All you need to do is plug it into your Fluke Multi Meter and clamp the spring loaded clamp around one leg of the circuit.  This way you do not need to disconnect any live circuits.


Also note that relays are not the only application where you might need to take a current reading on fire alarm circuits.  Other example applications may include NAC (Notification Appliance Circuits), Door Holder circuits, Magnetic Door Locks, etc.  Always remember that you need to verify that you are not over-loading the circuit based on the limitation set forth in the data sheets and instructions manuals.

This concept is no different that your house.  If you plug too many electronics into electrical outlets on one 120 VAC circuit then you are going to pop the breaker.  These limitations are put in place for the protection of the equipment as well as your personal safety.