SPEKTRUM 2.4 GHZ Digital Radio System User Manual


NOTICEAll instructions, warranties, and other collateral documents are subject to change at the sole discretion of Horizon Hobby, LLC. For up-to-date product literature, visit horizonhobby.com or towerhobbies.com and click on the support or resources tab for this product.

Meaning of Special Language

The following terms are used throughout the product literature to indicate various levels of potential harm when operating this product: WARNING: Procedures, which if not properly followed, create the probability of property damage, collateral damage, and serious injury OR create a high probability of superficial injury.CAUTION: Procedures, which if not properly followed, create the probability of physical property damage AND a possibility of serious injury.NOTICE: Procedures, which if not properly followed, create a possibility of physical property damage AND a little or no possibility of injury.

WARNING AGAINST COUNTERFEIT PRODUCTS: Always purchase from a Horizon Hobby, LLC authorized dealer to ensure authentic high-quality Spektrum product. Horizon Hobby, LLC disclaims all support and warranty with regards to, but not limited to, compatibility and performance of counterfeit products or products claiming compatibility with DSM or Spektrum technology.Age Recommendation: Not for Children under 14 years. This is not a toy.NOTICE: This product is only intended for use with unmanned, hobby-grade, remote-controlled vehicles. Horizon Hobby disclaims all liability outside of the intended purpose and will not provide warranty service related thereto.


Visit www.spektrumrc.com/registration today to register your product.


  • Always ensure all batteries have been properly chargedprior to using the model.
  • Always check all servos and their connections prior to each run.
  •  Never operate your model near spectators, parking areas, or any other area that could result in injury to people or damage of property.
  • Never operate your model during adverse weather conditions. Poor visibility can cause disorientation andloss of control of your model.
  •  Never point the transmitter antenna directly toward the model. The radiation pattern from the tip of the antenna is inherently low.
  • If at any time during the operation of your model you observe any erratic or abnormal operation,  immediately stop operation of your model until the cause of the problem has been ascertained and corrected.


Your new SR315/SLR300 Receiver has a special water-resistant coating on the electronics to ensure reliable performance in higher than average moisture conditions. This conformal coating can offer mild protection from light drops of water.

  • DO NOT submerge this product underwater for any period of time. If it is submerged, it may result in damage or loss of function.
  • DO NOT pour water onto or allow excess water to come in direct contact with the product.
  •  DO NOT operate this product in heavy rain or snow.
  •  DO NOT expose this product to saltwater (ocean water or water on salt-covered roads), contaminated or polluted water. In case of excess exposure to water or debris, immediately wipe down the SR315/SLR300  with a soft cloth, and allow it to fully dry before next use.NOTICE: Never use a pressure washer to clean your vehicle.NOTICE: Make sure the other components in your vehicle are waterproof or water-resistant before driving in wet conditions.


SPMRSLT300: SLT3 Transmitter onlySPMSLT300: SLT3 Transmitter and SR315 ReceiverSPMSLT310: SLT3 Transmitter and SLT300 ReceiverSLT3 TRANSMITTER FUNCTIONS

SpecificationsPower Supply: 4 AA BatteriesOperating Frequency: 2.4GHzTransmit Power: <100mwControl Protocol: SLTControl: Proportional Steering and Throttle/Brake with Trim Knobs, Third Channel with 3 Position  Momentary SwitchAuxiliary Functions: 3 Position Throttle Limit Switch, Steering Rate Knob to Change Steering Travel on-the-fly, Programmable Servo Travel for Steering and Throttle/BrakeA. Throttle TrimAdjusts the throttle neutral pointB. Steering TrimAdjusts the steering center point. Normally, the steering trim is adjusted until the vehicle tracks straight.C. LED

  • Solid red lights: Indicates the power is ON and adequate battery power
  • Flashing red lights: This indicates the battery voltage is critically low.

Replace batteriesD. Steering WheelE. Throttle/BrakeF. Steering RateOn-The-Fly knob for travel adjustment on the steeringG. Channel 33 position momentary switch, middle position is neutral For programming press up for the A button, press down for the B button

H. Throttle LimitLimits throttle output to 50/75/100%Select 50% or 75% for less experienced drivers or when you are driving the vehicle in a small area.I. Throttle (TH) Servo ReversingMove the switch to reverse the throttle channelJ. Steering (ST) Servo ReversingMove the switch to reverse the steering channelK. Power Button


This transmitter requires 4 AA batteries.

  1. Remove the battery cover from the transmitter.
  2.  Install the batteries as shown.
  3. Install the battery cover.

CAUTION: If using rechargeable batteries, charge only rechargeable batteries. Charging non-rechargeable batteries may cause the batteries to burst, resulting in injury to persons and/or damage to property. CAUTION: Risk of explosion if the battery is replaced by an incorrect type. Dispose of used batteries according to national regulations.


The servo travel on the Steering and Throttle channels can be adjusted through a special programming mode in the transmitter.

  1.  Begin with the transmitter binding process to the receiver complete. Power ON the receiver.
  2. Hold full right and full brake while powering the transmitter ON to put the transmitter into programming mode.The LED on the transmitter will flash 4 times to indicate it is in programming mode.
  3.  Turn and hold the wheel full left to set the travel limit for that direction, press the A button to increase travel, press the B button to reduce travel. The LED will flash once with every change. Return the wheel to the center to set the travel value.IMPORTANT: If the value has reached the maximum or minimum that can be accepted, the LED will not flash with further input.
  4. Turn the wheel to the right and repeat the process to set the steering travel to the right.
  5. For electric vehicles, power the Transmitter OFF to save the settings. Calibrate your ESC to the default throttle travel.
  6. For fuel-powered vehicles, set the throttle travel without the engine running; After setting steering travel, you can set throttle travel with the same process. Pull and hold full throttle, adjust travel with the A and B  buttons, return to the center to set the value.
  7. Push full brake, adjust travel with the A and B buttons, return to center
  8. Power the transmitter OFF to save the values.


There is a hidden mode if you want to reset the servo travel and calibration in the transmitter.

  1. Hold full left and full brake while powering the transmitter ON to put the transmitter into programming mode. The LED will flash 4 times then turns OFF to indicate factory reset.
  2. Release the wheel and throttle trigger back to neutral and the LED will illuminate to indicate factory reset is complete.
  3.  Power the transmitter OFF.


SpecificationsType: FHSS 2.4GHz SLT ProtocolDimensions (LxWxH): 33.4mm x 21mm x 12.6mm)Antenna Length: 140mmChannels: 3Weight: 6 gramsBand: 2.4GHzVoltage Range: 3.5–9.6VBind Type: Bind Plug


  1.  Insert the bind plug into the bind port on the receiver.
  2. Power on the receiver, the LED will flash rapidly to indicate it is in bind mode.
  3. Power on the transmitter; the LED light on the receiver will stop flashing and stay illuminated to indicate binding is complete.


Always set the failsafe position for zero throttles.

  1. Power on the TX and RX, make sure the transmitter and receiver are connected properly.
  2. Hold steering, throttle trigger, and AUX controls at the desired failsafe positions.
  3. Insert the bind plug into the bind port on the receiver; The LED on the receiver will flash 3 times and then remain lit to indicate the failsafe positions have been set.


  • When the receiver enters bind mode, the LED flashes rapidly.
  • If the receiver loses signal, the LED light flashes slowly to indicate it is in failsafe mode.
  • When the receiver is connected to the transmitter, the LED remains illuminated.
  • When setting the fail-safe positions, the LED light flashes three times and then remains illuminated.


SpecificationsType: Dual Protocol 3 Ch Receiver* (SLT/DSMR)Dimensions (LxWxH): 32.5 x 21.5 x 12.4mmAntenna Length: 229mmChannels: 3Weight: 6gBand: 2.4GHzVoltage Range: 3.5–9.6VBind Type: Bind ButtonFailsafe: Hold the steering wheel and throttle trigger in the desired failsafe positions during binding*SPMSR315 receivers included with the SPMSLT300 package include SLT and DSMR compatibility. If you have an SR315 receiver that was purchased by itself, you may need to install a firmware update to make your SR315 SLT compatible.


Binding is the process of programming the receiver to recognize the GUID (Globally Unique Identifier) code of a single specific transmitter.

  1. Power ON the receiver, press the bind button three times quickly (within 1.5 seconds). The LED will begin to flash with a pause.
  2. Set the trims and control positions at the desired failsafe settings, and power ON the SLT3 transmitter.
  3. When the LED on the SLT3 transmitter and receiver remain lit, binding is complete.

You must rebind when:

  • Different failsafe positions are desired e.g. when throttle or steering reversing has been changed.
  • Binding the receiver to a different transmitter.


The receivers feature a coaxial antenna design for easy installation in almost any model. Think of the last 1 inch (32mm) on the tip of the antenna as the active portion of the antenna, the coaxial portion leading up to it is just an extension. Install the antenna so the active portion is positioned as high as possible in the vehicle, and not “in the shadow” of any carbon fiber or metal. The case of the receiver can accept an antenna tube directly, making optimal antenna placement easy (antenna tube not included).WARNING: Do not kink, cut or damage the antenna wire. The antenna is made of a coaxial wire; if the outer sheath becomes damaged, the receiver will not work properly. If the antenna is damaged in any way, replace the antenna before attempting to use the receiver.


  1. Select a location to mount the receiver that is protected with good placement for the antenna. The antenna should be located as high from the ground as possible and away from conductive surfaces.
  2. Use double-sided tape, hook and loop material, or foam insulation in your mounting box to secure the receiver.
Problem Possible Cause Solution
The system will not connect

Your transmitter and receiver are too close together

Move transmitter 1 to 3 meters from receiver

You are around metal objects Move to an area with less metal
The receiver goes intofailsafe mode a shortdistance away from thetransmitter

Check the receiver antenna to be sure it is not cut or damaged

Replace the receiver or contact Horizon Product Support

Make sure your receiver antenna is in an antenna tube and is above the vehicle
The receiver quitsresponding duringoperation Inadequate battery voltage Charge batteries. Spektrum receivers require at least 3.5V to operate. An inadequate power supply can allow voltage to momentarily drop below 3.5Vand cause the receiver to brown out and reconnect
Loose or damaged wires or connectors between battery and receiver Check the wires and connection between the battery and receiver. Repair or replace wires and/or connectors0


What this Warranty CoversHorizon Hobby, LLC, (Horizon) warrants to the original purchaser that the product purchased (the “Product”) will be free from defects in materials and workmanship for a period of 1 year from the date of purchase.

What is Not CoveredThis warranty is not transferable and does not cover (I) cosmetic damage, (ii) damage due to acts of God, accident, misuse, abuse, negligence, commercial use, or due to improper use, installation, operation, or maintenance, (iii) modification of or to any part of the Product, (iv) attempted service by anyone other than a Horizon Hobby authorized service center, (v) Product not purchased from an authorized Horizon dealer, (vi) Product not compliant with applicable technical regulations, or (vii) use that violates any applicable laws, rules, or regulations.OTHER THAN THE EXPRESS WARRANTY ABOVE, HORIZON MAKES NO OTHER WARRANTY OR REPRESENTATION, AND HEREBY DISCLAIMS ANY AND ALL IMPLIED WARRANTIES,INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE PURCHASER ACKNOWLEDGES THAT THEY ALONE HAVE DETERMINED THAT THE PRODUCT WILL SUITABLY MEET THE REQUIREMENTS OF THE PURCHASER’S INTENDED USE.Purchaser’s RemedyHorizon’s sole obligation and purchaser’s sole and exclusive remedy shall be that Horizon will, at its option, either (I) service, or (ii) replace, any Product determined by Horizon to be defective. Horizon reserves the right to inspect any and all Product(s) involved in a warranty claim. Service or replacement decisions are at the sole discretion of Horizon. Proof of purchase is required for all warranty claims. SERVICE OR REPLACEMENT AS PROVIDED UNDER THIS WARRANTY IS THE PURCHASER’S SOLE AND EXCLUSIVE REMEDY.

Limitation of LiabilityHORIZON SHALL NOT BE LIABLE FOR SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, LOSS OF PROFITS, OR PRODUCTION OR COMMERCIAL LOSS IN ANY WAY, REGARDLESS OF WHETHER SUCH CLAIM IS BASED ON CONTRACT, WARRANTY,TORT, NEGLIGENCE, STRICT LIABILITY, OR ANY OTHER THEORY OF LIABILITY, EVEN IF HORIZON HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Further, in no event, shall the liability of Horizon exceed the individual price of the Product on which liability is asserted. As Horizon has no control over use, setup, final assembly, modification, or misuse, no liability shall be assumednor accepted for any resulting damage or injury. By the act of use, setup, or assembly, the user accepts all resulting liability. If you as the purchaser or user are not prepared to accept the liability associated with the use of the Product, the purchaser is advised to return the Product immediately in new and unused condition to the place of purchase.

LawThese terms are governed by Illinois law (without regard to conflict of law principles). This warranty gives you specific legal rights, and you may also have other rights which vary from state to state. Horizon reserves the right to change or modify this warranty at any time without notice.

WARRANTY SERVICESQuestions, Assistance, and ServicesYour local hobby store and/or place of purchase cannot provide warranty support or service. Once assembly, setup, or use of the Product has been started, you must contact your local distributor or Horizon directly. This will enable Horizon to better answer your questions and service you in the event that you may need any assistance.For questions or assistance, please visit our website at www.horizonhobby.com, submit a Product Support Inquiry, or call the toll-free telephone number referenced in the Warranty and Service Contact Information section to speak with a Product Support representative.

Inspection or ServicesIf this Product needs to be inspected or serviced and is compliant in the country you live and use the Product n,  please use the Horizon Online Service Request submission process found on our website or call Horizon to obtain a Return Merchandise Authorization (RMA) number. Pack the Product securely using a shipping carton.  lease note that original boxes may be included, but are not designed to withstand the rigors of shipping without additional protection. Ship via a carrier that provides tracking and insurance for lost or damaged parcels, as Horizon is not responsible for merchandise until it arrives and is accepted at our facility. An Online Service Request is available at http://www. horizonhobby.com/content/service-center_render-service-center. If you do not have internet access, please contact Horizon Product Support to obtain an RMA  number along with instructions for submitting your product for service. When calling Horizon, you will be asked o provide your complete name, street address, email address, and phone number where you can be reached during business hours. When sending products into Horizon, please include your RMA number, a list of the included items, and a brief summary of the problem. A copy of your original sales receipt must be included for warranty consideration. Be sure your name, address, and RMA number are clearly written on the outside of the shipping carton.

NOTICE: Do not ship LiPo batteries to Horizon. If you have any issues with a LiPo battery, please contact the appropriate Horizon Product Support office.

Warranty RequirementsFor Warranty consideration, you must include your original sales receipt verifying the proof-of-purchase date. Provided warranty conditions have been met, your Product will be serviced or replaced free of charge. Service or replacement decisions are at the sole discretion of Horizon.Non-Warranty ServiceShould your service not be covered by warranty, service will be completed and payment will be required without notification or estimate of the expense unless the expense exceeds 50% of the retail purchase cost. By submitting the item for service you are agreeing to payment of the service without notification. Service estimates are available upon request. You must include this request with your item submitted for service. Non-warranty service estimates will be billed a minimum of ½ hour of labor. In addition, you will be billed for return freight. Horizon accepts money orders and cashier’s checks, as well as Visa, MasterCard, AmericanExpress, and Discover cards. By submitting any item to Horizon for service, you are agreeing to Horizon’s Terms and Conditions found on our website http://www.horizonhobby.com/content/service-center_render-service-center.ATTENTION: Horizon service is limited to Product compliant in the country of use and ownership. If received, a non-compliant Product will not be serviced. Further, the sender will be responsible for arranging return shipment of the un-serviced Product, through a carrier of the sender’s choice and at the sender’s expense. Horizon will hold non-compliant Products for a period of 60 days from notification, after which they will be discarded.


Country of Purchase Horizon Hobby Phone Number/Email Address Address
North America Horizon Service Center

(Repairs and Repair Requests)

servicecenter.horizonhobby.com/RequestForm/ 2904 Research Rd  Champaign, Illinois, 61822 USA
Horizon Product Support

(Product Technical Assistance)

[email protected]
Sales [email protected]
European Union Horizon Technischer Service [email protected] Hanskampring 9 D 22885 Barsbüttel, Germany
Sales: Horizon Hobby GmbH +49 (0) 4121 2655 100


FCC ID: BRWSPMSLT300, BRWSRIRVINGV1FCC NOTE: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:(1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.


NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules.These limits are designed to provide reasonable protection against harmful interference in a residential installation.This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.

However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the equipment and receiver.
  • Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
  •  Consult the dealer or an experienced radio/TV technician for help.The device has been evaluated to meet the general RF exposure environment. To maintain compliance with FCC’s RF exposure guidelines, the distance must be at least 20cm between the radiator and your body and fully supported by the operating and installation configurations of the transmitter and its antenna(s)


IC: 6157A-SPMSLT300, CAN ICES-3 (B)/NMB-3(B)This device complies with ICES Canada license-exempt RSS standard(s). Operation is subject to the following two conditions:(1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.


Horizon Hobby, LLC hereby declares that this product is in compliance with the essential requirements and other relevant provisions of the RED Directive.A copy of the EU Declaration of Conformity is available online at:http://www.horizonhobby.com/content/support-render-compliance.Frequency Band: 2403-2480 MHzMax EIRP: 45mW

Instructions for Disposal of WEEE by Users in the European UnionThis product must not be disposed of with other waste. Instead, it is the user’s responsibility to dispose of their waste equipment by handing it over to a designated collection point for the recycling of waste electrical andelectronic equipment. The separate collection and recycling of your waste equipment at the time of disposal will help to conserve natural resources and ensure that it is recycled in a manner that protects human health and the environment. For more information about where you can drop off your waste equipment for recycling, please contact your local city office, your household waste disposal service, or where you purchased the product.

© 2020 Horizon Hobby, LLC.DSM, DSM2, DSMR, SLT3, and the Horizon Hobby logo are registered trademarks of Horizon Hobby, LLC.The Spektrum trademark is used with the permission of Bachmann Industries, Inc.Created: 7/2020SPMRSLT300, SPMSLT300, SPMSLT310


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