Frequently Asked Questions

Signals View All the Answers

  • What's wrong if the strobe does not flash, but the horn is working fine?
    • Check the input voltage. If input voltage is pulsing, the strobe will not work. The strobe needs a steady power source or power from fire alarm control panel that includes the Gentex synchronization protocol. No Gentex Fire Protection Products will work on a pulsing or coded circuit.
  • What candela rating is a 15/75?
    • 75cd as measured by UL1638 on-axis and 15cd as measured by ANSI/UL1971 where specific candela is required by each viewing angle.
  • Does Gentex manufacture an addressable signaling appliance?
    • No.
  • Does Gentex manufacture an explosion-proof product?
    • No, contact Commercial Products at 1-800-521-8219.
  • What's wrong if the strobes are flashing slowly while the horns are working fine?
    • Power supply is resetting. It takes 2 seconds once power is applied for the strobes to flash and the power supply is resetting before the 2 seconds. To troubleshoot: cut loop in half or take all the units off and start adding one back on at a time until the problem starts again.
  • What does the term "Anechoic Chamber" mean?
    • It means a room with walls that completely absorb sound. It is often used to provide standardized measurement conditions for audio devices. A bedroom with a lot of drapes and soft furnishings approaches this condition. The room is often referred to as "dead". 
  • What does the term "Reverberant Chamber" mean?
    • It means a room with walls that completely reflect sound. It is often used to provide standardized measurement conditions for audio devices. A restroom with hard tiles and surfaces approaches this condition. The room is often referred to as "live". 
  • Who determines the end-of-line resistor value?
    • It is determined by the panel manufacturer. 
  • What are the ADA requirements for sleeping area?
    • ADA requires a minimum of 177 candela in a sleeping area when mounted less than 24" from the ceiling (110 cd more than 24" from ceiling). 
  • How do you calculate how many strobes and horn strobes you can use?
    • Example: using a 3 amp circuit (3.00 which Gentex synchronization module is rated for) and unit that draws 87mA: 3/0.087 = 34.48 or 34 units. If a NAC panel is being used, figure the calculations with a 2 amp circuit.
  • How can the horn and strobe be isolated on a Gentex horn/strobe unit; functioning only the strobe portion of the unit?
    • Wire in through the S+ and S- and place switch 1 and 2 in the OFF position. This will isolate the horn and strobe.

Syncronization Modules

  • How many circuits can you have on the AVS module?
    • Two class B circuits or one class A circuit.
  • How many modules can you sync together?
    • There is no limitation to how many modules you wire together.
  • Will the Gentex sync module work with other manufacturers' devices?
    • No, our module works only with our devices. 
  • Does the module come with a backbox?
    • Yes.
  • Can the AVS module sync through a power supply?
    • No, The module is designed to go between the power supply and signals.
  • How do you wire master and slave modules together?
    • Go from the master module positive output 1 and negative 1 to the sync positive and negative on the slave modules (reference drawing 6B on AVS Data Sheet).
  • How do you silence the horns while the strobes are still flashing using the module?
    • Go from your NAC circuit on the panel to H+ H- on the module and 
      remove the jumper. This will be your silencing circuit.
  • What type of power is to be applied to a synchronization module?
    • A steady DC power is to be applied, without any other protocol (including temporal 3).

Smoke Alarms

  • How many legacy Gentex smoke alarms can be tandem interconnected?
    • Up to 12 legacy Gentex smoke alarms without relay contacts can be tandem interconnected and up to 6 legacy Gentex smoke alarms with relay contacts can be interconnected. Legacy smoke alarms with and without relay contacts may also be interconnected (example: 12 legacy smoke alarms without contacts may be interconnected with up to 3 legacy smoke alarms with contacts). The reason for the limitation of 6 legacy Gentex smoke alarms with contacts is due to the voltage drop in the tandem line; the contacts pull the voltage.
  • How many Dualink® Gentex smoke alarms can be tandem interconnected?
    • Up to 12 Dualink® Gentex smoke alarms with or without relay contacts can be tandem interconnected. Due to technology advancements of the Dualink® Gentex smoke alarms, the voltage drop in the tandem line can hold the additional smoke alarms with relay contacts.
  • How many combination smoke alarms and carbon monoxide alarms can be interconnected?
    • Per NFPA 72, 2010 Edition, Chapter 29.8.2.2(2), the interconnection of smoke alarms or heat alarms shall comply with the following: In no case shall more than 18 initiating devices be interconnected (of which 12 can be smoke alarms) where the interconnecting means is not supervised.
  • What is a Dualink® feature alarm?
    • Gentex Dualink® feature allows full tandem capabilities with all Gentex tandem interconnect capable smoke alarms, CO alarms, and combination smoke/CO alarms (reference Dualink® information).
  • What alarm series are classified as Legacy Smoke Alarms?
    • 7100/7103 Series
    • 7200/7203 Series
    • 9120/9123 Series
    • 9220/9223 Series
    • 710CS/713CS Series
    • 7109CS/7139CS Series
    • GN-200/GN-203 Series
    • GN-300/GN-303
    • HD135/HD135-220 Series
  • Will the GN-503FF tandem interconnected with all Gentex tandem capable alarms?
    • The GN-503FF is only capable of tandem interconnect with the GN-503FF, GN-503, GN-503F, CO1209, CO1209F, S1209 and S1209F. The GN-503FF is not able to tandem interconnect to any other Gentex products other than what is listed above.
  • What alarm products are classified as Dualink® Alarms?
    • S1209 and S1209F 
    • CO1209 and CO1209F 
    • GN-503 and GN-503F 
  • Does Gentex have a trouble relay for loss of power?
    • No. If power is lost, the relays will not transfer. Relays will only transfer if detector goes into alarm.
  • What is the difference between integral thermal and isolated thermal?
    • Integral thermal (T) = the detector itself will go into alarm when it reaches determined heat. On the (TF) models, when thermal is activated it will activate the sounder and the relay contacts. The integral heat sensor activates the smoke alarm and cannot connect into a panel or annunciator.

      Isolated thermal (H) = two wires directly in back of unit that you connect into a panel or annunciator and when heat temperature is met it will set the panel or annunciator into alarm. On the (HF) models, the heat thermal will activate whatever is wired to it. Isolated thermal/sensor is isolated from the smoke alarm, therefore horn will not sound.
  • Does Gentex have a supervised relay?
    • No.
  • What is the voltage on the tandem wire of Gentex smoke alarms?
    • When activated 9.5 volts and no voltage in the standby mode.
  • If the smoke alarm loses power will the relays and tandem line work on battery back up?
    • Yes.
  • Can a 24VDC horn, horn/strobe, or strobe be connected from the relay contact?
    • Yes, will need to run a 24VDC power supply to the relay contact.
  • Are the contacts dry contacts?
    • Both contacts are dry contacts and have no voltage.
  • How often should the 9VDC battery on the Gentex 9120 and 7109 smoke alarm series be replaced?
    • Recommended replacement of the 9VDC battery once a year; or when the unit chirps.
  • Does Gentex manufacture a trouble contact?
    • No, Gentex does not manufacture a trouble contact.
  • Can the smoke alarm detect cigarette smoke?
    • No. Contact Voice Products at 1-216-360-0433.
  • How do you connect a GXS120 strobe to the 7100F/9120F, 710/7109CS?
  • What is the difference between the 710/7109CS and the 710/7109CSX?
    • The CSX allows you to trip the strobe (strobe only) from the fire alarm panel.
  • How do you test the smoke alarms with the heat thermals?
    • Use a hair dryer or a soldering iron.
  • What is the frequency on the smoke alarms?
    • The piezo is 3100Hz.
  • What is the smoke alarm housing made of?
    • The round 7000/8000/9000 Series alarms are made of flame resistant PVC. The square 7100 Series are made of flame resistant Noryl. The GN Series are made of flame resistant ABS.
  • When the smoke alarms are hooked in tandem, how can you tell which one is initiating?
    • The red light will be pulsing on the smoke alarm that initially went into alarm.
  • What size area does a Gentex smoke alarm cover?
    • 30' X 30' space. Refer to NFPA 72-2010, Section 17.7.3.2.3.1.
  • Where are Gentex smoke alarms and smoke detectors manufactured?
    • Gentex smoke alarms and smoke detectors are assembled in Zeeland, Michigan, USA
  • How should Gentex smoke alarms and smoke detectors be disposed of?
    • Gentex smoke alarms and smoke detectors are photoelectric type and do not contain any radioactive materials. The smoke alarms and smoke detectors should be recycled if facilities are available in your area.
  • When turning the test knob to Test 1 or holding the test button, will the contacts change states?
    • Yes.
  • Are Gentex single/multiple station smoke alarms always non-latching (self-restoring)?
    • Yes. Per ANSI/UL 217, all single/multiple station smoke alarms are to be non-latching (self-restoring) devices.
  • Will a lithium battery work on Gentex Series smoke alarms with battery back-up?
    • No, the UL approved battery for Gentex Series smoke alarms with battery back-up is the Duracell MN 1604 battery.
  • Why is it recommended that Gentex smoke alarms and smoke detectors be replaced every ten years?
    • Gentex products are in compliance with NFPA codes. Per NFPA 72, 2010 Chapter 29.8.1.4(5)(b), "Smoke alarms installed in one and two family dwellings shall not remain in service longer than 10 years from the date of manufacture."

System Detectors

  • Can you use the Gentex 8000 series as a stand-alone unit?
    • 8000 series is not classified as a stand alone unit. The unit will need to hook into a panel or a power supply. When using the system detectors for releasing services, the unit does not have to hook up to a panel (Ex. Elevator recall and door holders).
  • Can the 8240 Series that includes the P (piezo) option be hooked in tandem?
    • 8240 Series with P option does not have tandem capabilities, however if the panel has a reverse polarity feature then all of the smoke detectors will sound. Reference Technical Bulletin #1.
  • How do the 8000 series latching detectors reset?
    • The only way to reset the latching detectors is to physically drop power to unit.
  • If hooking up the 8240 series smoke detector into a fire alarm panel, and someone removes the head of the detector, will it put the panel into trouble?
    • Only if it is on a supervised loop.  
  • What does reverse/local piezo mean?
    • Piezo will alarm locally, reverse voltage at the control panel to sound all horns on the circuit.
  • If we need the contact to close upon alarm, which contact wire do we use?
    • You will use a normally open contact, violet and violet/black or the blue and orange wire.
  • If we need the contact to open upon alarm, which contact wire do we use?
    • You will use a normally closed contact, the orange and yellow wire.
  • Since the 8000 series smoke detectors do not have the tandem connection, is it okay to mix them with other manufacturers in a series on a panel?
    • Yes because the 8000 series is a 4 wire detector and does not receive its power from an initiating circuit.
  • Does Gentex manufacture two- or four-wire smoke detectors?
    • The Gentex 8000/8003 Series are four-wire smoke detectors.
  • What is the difference between a two-wire and four-wire smoke detector?
    • A four-wire smoke detector uses two of the four wires for power and the other two wires for the alarm. A two-wire smoke detector uses the same two wires that power them to detect an alarm.
  • Does Gentex have a single pull, double throw contact?
    • Yes, the form C accessory contact.
  • Are the contacts dry contacts?
    • Both contacts are dry contacts and have no voltage.
  • What type of end-of-line resistor is needed on the 8000 series smoke detectors?
    • This information needs to come from the panel manufacturer.
  • Where are Gentex smoke alarms and smoke detectors manufactured?
    • Gentex smoke alarms and smoke detectors are assembled in Zeeland, Michigan, USA
  • How should Gentex smoke alarms and smoke detectors be disposed of?
    • Gentex smoke alarms and smoke detectors are photoelectric type and do not contain any radioactive materials. The smoke alarms and smoke detectors should be recycled if facilities are available in your area.
  • When turning the test knob to Test 1, will the contacts change states?
    • Yes.
  • Why is it recommended that Gentex smoke alarms and smoke detectors be replaced every ten years?
    • Gentex products are in compliance with NFPA codes. Per NFPA 72, 2010 Chapter 29.8.1.4(5)(b) "Smoke alarms installed in one and two family dwellings shall not remain in service longer than 10 years from the date of manufacture."

Important Notice


The materials included on this website, including the Literature/Reference Material (e.g., technical bulletins, application guides, manuals, and reference materials), have been prepared by Gentex Corporation ("Gentex") for informational purposes only, are necessarily summary, and are not purported to serve as legal advice and should not be used as such. Gentex makes no representations and warranties, express or implied, that these materials are complete and accurate, up-to-date, or in compliance with all relevant local, state, and federal laws, regulations, and rules. The materials do not address all legal considerations as there is inevitable uncertainty regarding interpretation of laws, regulations, and rules and the application of such laws, regulations, and rules to particular fact patterns. Each person's activities can differently affect the obligations that exist under applicable laws, regulations, or rules. Therefore, these materials should be used only for informational purposes and should not be used as a substitute for seeking professional legal advice. Gentex will not be responsible for any action or failure to act in reliance upon the information contained in this web site.