Rx6x Features (v6.0.3)


This page describes Rx6x features in a little detail. These receivers have some 'depth'. You are not expected to use every feature and receivers come with default settings that meet common needs. But when you want to add a new feature like controlling lights or using different sticks for functions, the flexibility is there.


This Rx is compatible with DSM2 and DSMX transmitters. Most joysticks, switches and knobs on hobby transmitters control separate 'channels'. These are numbered and have some common names which are referred to below (eg: Ch1 Throttle). All outputs on the Rx can be used with any channel.


Each Rx has an operating voltage range. They all work down to 3v and some work up to 16v DC. This allows it to be used with many battery combinations. 1S, 2S and 3S lipos are common choices (3S = 3 cells in series).

The motor output of each receiver has a current rating which should not be exceeded. This is usually given as a maximum value which equates to the motor stalled at 100% throttle.

There are no minimum or maximum battery capacity requirements (mAh).


The Rx can be powered from rail track power including DCC. A bridge rectifier is needed on the train to handle AC or reverse DC polarity. A capacitor is needed on the train to reduce brownouts/LVC (5-flash on Rx). A regulator is needed if track voltages exceed 16v.


The Rx has an integrated forward/reverse motor controller for brushed motors (ESC). With this setting, one channel is used to control the motor in both directions. Center is off. Any channel can be used. Rx6x-2 has this setting for Tx21. Rx6x-3 is more suitable for joystick Tx's.


This option uses two channels to control the motor. Full stick movement of one channel is used to control the power level regardless of direction. Low is off. Any channel can be used. Rx6x-1 has this setting and is suitable for Tx21 and any joystick Tx.

Forward/reverse direction is set with a second channel. Direction can be changed at any time but only takes effect when the throttle is closed and reopened. If the Direction channel is a self-centering joystick you simply push it in the required direction and let the stick center again. If it is a 2-position switch like on Tx21 it is toggled and left in the required direction.


The motor output can be made to drive a servo instead of a motor. This is not a common use for the motor output. The output pulses will be at battery voltage so may need to be reduced using an external 3.3-5v zener diode and resistor.


The power level can be made to go quicky to a minimum level as the throttle is opened. It can be set to 0 to 100%. The default is 0%.


The maximum power level available at full stick can be reduced to match engine speeds for a consist. It can be set to 0 to 100%. The default is 100%.


The motor's direction of rotation can be reversed using this programmable setting. This may simply be for convenience or to make a temporary change to suit a push/pull consist. This feature affects the Directional Light feature.

Another way of reversing the motor direction is to place the throttle at max before the Rx is switched on. The motor's direction will toggle each time you do this. Both techniques have the same result. Changing the motor direction with this approach also affects the Directional Light feature.


Motor speed is regulated with PWM. The default PWM frequency is 'auto' which uses 16kHz at low voltages and 60 or 250Hz with higher voltages (60Hz on receivers intended for trains). This can be changed to fixed frequencies but the receivers are not rated for max Frequency at max Voltage and max Current.


Softstart smooths changes to motor power. By default it takes a little under 0.5s to go from 0 to 100% throttle. This can be made more or less responsive.


Lipos are damaged if over-discharged. The Rx cuts power to the motor when the voltage falls too low. Power can be applied to the motor again if the operator first closes the throttle. Recharge your battery when this happens. Cut-off levels for voltages measured when the Rx was switched on are listed below. Measurements should be within 2% accuracy.

3v for <4.3v measured at startup
4v for 4.3-6v
6v for 6-9v
9v for >9.1v


If an external voltage booster powered with a 1S lipo is used, the Rx can monitor the lipo's voltage if the booster does not do this. The Rx will cut power to the motor when the lipo voltage falls to 3v. More details.


The Rx is compatible with:
- DSM2 'Air' transmitters
- DSMX 'Air' transmitters
- DSM2 'Surface' transmitters (steering wheel/throttle trigger)


The Rx has to be 'paired' with your Tx. This is called Binding. You only have to bind once. Your Tx can be bound with any number of compatible Rx's. The Rx can only be bound with one Tx at a time.

Auto Bind: The Rx will enter bind mode about 22s after being switched on. The led will flash fast. You then hold the bind button in on your Tx and switch the Tx on. The led should flash for a few seconds and then come on solid. Job done. If a bind signal is not detected within 1 minute, the Rx will exit bind mode.

Manual Bind: If this option is enabled, you have to connect the two pads together and then switch the Rx on. The Rx will enter bind mode immediately. The led will flash fast. Remove connection between pads. Same procedure with Tx as above.


The Rx will go into sleep mode to save power if the throttle is not changed for an extended period of time. The time to enter sleep mode can be set between 1 and 6 hours or 'never' (sleep disabled). The default is 1hr. The Rx has to be switched off and back on to use it again.

The Rx draws 1mA in sleep mode. This is not normally a substitute for an on/off switch. However, the sleep function does switch receivers with an integrated On/Off reed switch 'completely' off (Rx62/Rx64). So with these two receivers, sleep is an acceptable technique for switching them off.


Rx62 and Rx64 have an integrated On/Off switch. They are supplied with a reed switch which is toggled with an external magnet brought in close proximity for a second or two. The receiver needs to be mounted away from other magnetic fields such as motors and speakers. The reed switch itself simply acts as a momentary action switch to toggle other electronics on/off. So a small push-button switch can be wired in place of or in parallel with the reed switch on the Rx. A switch like this can be flush-mounted, operated with a 'pin' through a small hole, or by gluing any external 'lump' to the push-button mounted inside the model. Tactile switches are often very suitable for this.

It is helpful to be able to see the led on the Rx so you know if it is on or off. The 'LED2' feature can help in this regard. Alternatively simply wait a few seconds and test whether the Tx can operate the model.

A big benefit of this on/off feature is the Rx can be switched off remotely from the Tx. Naturally this does require that you have established a radio connection and the model is working normally. The default setup is that you press and hold the Bind button for 5s to switch the receiver off (Ch5 low). The activating channel and time period can be changed.


The normal behaviour of the Rx on signal loss is to stop the motor. It holds the last known throttle position for 1 second and then closes the throttle smoothly over another 3 seconds. This can be reduced to 1s for a quicker response. Switching the Tx off is one way of invoking an emergency stop. Control can be restored by switching the Tx back on.

When the Rx is controlling a train on a continuous loop, it can be made to continue running in two ways:
(1) When you deselect the loco using the 'Selecta' feature, Rx6x-22 receivers are configured to 'continue' running. They will stop if the Tx is switched off (emergency stop).
(2) When you set failsafe to the SLEEP time. If the Tx is switched off the train will continue running until the sleep timer expires (eg: after 1 hour). If the sleep time is set to 'never sleep' the train will continue running forever. Control can be restored by switching the Tx back.

In all cases, if LVC (low voltage cutoff) is enabled the LVC function will stop the motor when the battery reaches the minimum voltage.

[LED2] - LED2

The led on the Rx often reveals the state it is in. If the Rx is concealed in a model and another led is being controlled by one of the 'P' outputs, the Rx's led activity can be mirrored on that other led. This mirroring only occurs up until the Rx become Armed. Once armed the 'LED2' activity stops and the normal activity of that output commences. So for example, the front light on a car or train can reveal what the Rx is doing as it starts up, binding, programming, etc and then operate as a front light in normal use.

Two 'enabled' options exist. The 2-flash option is as described above. The 3-flash option suppresses the flashes every 2s when the Rx is scanning for a signal.


This is a standard servo output. The position of the servo is proportional to the position of the controlling channel. It can control a servo or external ESC (eg: brushless). Rx61 has a 4v BEC to power a small servo (up to about 2g in weight).

There are some options for how the output works:
1. Speed setting '1' is normal. The servo simply moves to wherever the channel tells it at normal speed.
2. Speed settings '2-6' make the servo change position more slowly. This is intended to be used when operating a coupling, hatch, etc. with a switched channel (eg: Ch5 Gear).


This feature gives full servo movement from a half stick movement on the Tx. It is intended to operate a coupling with a self-centering joystick where mid-stick is the closed position for the coupling.

The servo is at one extreme when the stick is centered (coupling closed). The servo moves to its other extreme in a proportional manner as the stick is moved (eg: to the right) to open/release the coupling. The servo returns the coupling to its closed/locked position when the stick is centered. The servo does not move when the stick is moved the other way.


This feature provides two servo type outputs whose controlling channels are mixed. It can be used to operate two servos or two external ESC's (eg: differential thrust steering for tank, digger, boat, blimp, etc).


A brake light can be made to come on automatically when the throttle is closed. The time that the led is on for can be adjusted from 1-6 seconds with the [BR_ON] setting. The brake light also comes on if the Rx is receiving a signal but is prevented from being armed because the throttle is not closed.

A reversing light can be made to come on automatically while the throttle is in the reverse position.


Two outputs can be configured for left/right indicators. The Activating Channel (eg: Ch4 Rudder) represents the stalk/switch used on a motor vehicle. The Steering Channel (eg: Ch2 Aileron) is the channel used for steering the vehicle. Only the Activating channel can start the indicators flashing. Both channels can cancel them.

The 'trim' on the Tx for the Steering channel often has to be used to make the vehicle run straight. In order to have a true center/narrow deadband for cancelling the indicators, the position of the Steering channel is detected automatically each time the Rx is switched on.

A quick movement of the Activating channel left or right (<2 seconds) starts an indicator flashing. A movement to the Left held for >2 seconds makes both indicators flash as Hazards. The same movement cancels the Hazards.


One output can made to flash rapidly to simulate an emergency light. If Indicators are enabled, the Flasher must use the same Activating channel. A movement to the Right held for >2 seconds starts or stops the Flasher.


Outputs are ON while the Tx stick/switch is deflected. Each channel can control two outputs (1 'left', 1 'right'). Both are OFF at center.


Outputs toggle ON or OFF each time the Tx stick/switch is deflected. Each channel can control two outputs (1 'left', 1 'right'). Each output latches ON or OFF until the stick is deflected after having been centered.


This feature is the same as above except that the time a channel is deflected can be used to operate two outputs each way. Each channel can control four outputs (2 'left', 2 'right'). One output on each side toggles ON or OFF each time the Tx stick/switch is deflected for <2 seconds. A second output on each side toggles ON or OFF each time the Tx stick/switch is deflected for >2 seconds.


A Front and Rear light is controlled automatically based on motor direction. This is often used on a train. Both lights start OFF and either the Front or Rear light is switched ON when you open the throttle for the first time. That light stays on until you change direction. The light stays on when you stop. The 'direction' of operation is changed when the Motor Reverse [M_REV] is changed. The function can only be used on 2 designated pads and both are set up by programming one of them.

If a channel number is assigned (1-10), the function can be switched on or off by radio. One light will always be on when the chosen channel is 'high' and both lights stay off when the channel is 'low' (from v603-4 this is the 3-flash in column 5). A push-button or joystick can also be used instead of a toggle switch to toggle the feature on and off (from v603-4 this is the 1-flash or 2-flash in column 5). The 1-flash would be used with the Tx20/21/22/23 Bind button (Ch5).

If no channel number (0) is assigned, the feature operates as described but one light will always be on and both cannot be switched off.

The IR options operate an Infrared led on a model. Only one IR output must be enabled. The model needs an IR led with current limiting resistor. The layout needs a microprocessor controlled sensing system with a 56kHz 'IR Receiver' (TSOP32156 or TSOP34156). The IR output is enabled while the throttle is on. The IR output is only on every 6s when the motor is off.

[IR1] - IR LED 1

IR1 is used to manually trigger features in a layout. For example, the led on a train can activate points/turnouts in the track when a button is pressed on the Tx. The output is off when the IR1 channel is centered. The output is on when deflected and the 'high' and 'low' positions send out different signals.

[IR2] - IR LED 2

IR2 is intended to automatically identify a moving object to a layout. For example, the led on a train could trigger a 'follow me' sound system. IR2 outputs a static address to identify up to 64 models to the sensing system.

[IR3] - IR LED 3

IR3 is the same as IR2 but the address is the position of a controlling channel. So this has a dynamic address which can be changed from the Tx. For example, it could be used to identify the Tx22 Selecta switch position and thus which loco is running when the others are stopped.

[IR4] - IR LED 4

IR4 is a telemetry feature which outputs the battery voltage. This helps estimate when to recharge because voltage falls as capacity is used up. There would normally be one sensor in a layout and models simply pass over it to have their battery voltage displayed.

[IR5] - IR LED 4 + 1

This option outputs the IR4 voltage while the IR1 channel is centered (IR1 off). When the IR1 channel is deflected (on), the output alternates between IR1 and IR4.

[IR6] - IR LED 4 + 1 + 2

This option alternates between IR2 (static address) and IR4 (voltage) while the IR1 channel is centered (IR1 off). When the IR1 channel is deflected (on), the output alternates between IR2 and IR1.

[IR7] - IR LED 4 + 1 + 3

This option alternates between IR3 (dynamic address) and IR4 (voltage) while the IR1 channel is centered (IR1 off). When the IR1 channel is deflected (on), the output alternates between IR3 and IR1.


The position of all channels can be output on 1 pad to feed another module. This option uses RS-232 async serial, 8 bit, no parity, 2 stop bits, LSB first. 3 speeds are available (125kb, 250kb and 500kb). Serial outputs normally occur every 22ms but cease for about 66ms every 1sec while the Rx does something else. The serial output is not possible if IR2 or IR3 are enabled.

1. The first 2 bytes are used to indicate the start of a sequence. Their values are 0xFE and 0x02.

2. The data feed then contains 2 bytes per channel. The high or low byte can be first in each pair. Each channel is output in numeric order (Ch1 first). This data contains the channel position in a 10 bit form (0-1023) with no channel number indicator. The feed provides data for every Tx channel but no less than 7 (even if not relevant).

3. Channel data is followed by 1 byte voltage indicator in tenths of a volt (eg: 36 is 3.6v). It should be accurate to 0.1v.

4. There is then a 1 byte signal strength indicator (RSSI) which has a 0-31 scale.

5. The final 1 byte is a checksum and is the sum of all other bytes cast to 1 byte.


The position of all channels can be output on 1 pad to feed another module. This option uses timed PPM pulses with 300us trigger pulses. All transmitter channels are output, but never less than 7 even if not controlled by the Tx. Channels are output in numeric order, Ch1 first. Frame length can be longer but not less than 22ms. The gap between frames can be longer but not less than 3ms. The SumPPM frame runs independantly of the radio. Channel positions are updated in the gap between frames.

The output can idle high (trigger pulses go low) or idle low (trigger pulses go high). An extra pulse can be added at the end to represent signal strength (RSSI). Divide that converted 10bit 'channel position' by 32 to get RSSI (0-31). No servo pulses are possible if SumPPM is enabled. Serial and SumPPM can be enabled on different pads at the same time but this may cause jitter.


Rx6x receivers are available in several variants (eg: Rx60-1, Rx60-2, etc). Each variant has settings to suit different types of transmitter or application (eg: cars, trains, etc). From version 603-3, variants can be changed either as a programming option (using a joystick transmitter or Prog1) or with Prog2 (shops).

The 'Factory Reset' option does not change the 'variant' but puts all the settings back to how the current variant is normally supplied from new.


'Selecta' allows receivers to be made active or inactive from the Tx. This allows you to expand the number of functions controlled using two or more receivers, or lets you hop between several models bringing them in and out of service without touching them. This is done by associating each Rx with a position on an activating channel. See video.


One channel is used to select models. The position of this channel is memorised during binding. The Rx responds to the Tx only when the channel is in that position. A 'switched' channel is the most practical. However, the 'trim' on a joystick channel can also be used to select up to 5 models. Tx22 is designed specifically for trains and has a 12-position 'loco selector switch'. More details.


The normal and safe behaviour when a model is made inactive is for the motor to stop. When the model is something like a train on a continuous loop, the 'continue' option can keep everything running while you use the Tx to operate another model. More details.


Two Tx's can be associated with each model. If you flick the switch, the motor in the current active model will stop and it will seek out the other Tx. The 2nd Tx will have to accept the model to take control. More details.


This option is only relevant to Tx Change. More details.


'Programa' indicates a capabilty for changing settings in the Rx with a handheld programming device. You make choices on the programa device and press a button to update the Rx at any time. Settings can also be changed using a hobby Tx. The structure for all changes are in Programming Tables (eg: Rx61).

Prog1 is used to change settings in the programming table, one row at a time. It uses 5 pins to set values for the 5 columns of the chosen row.

Prog2 is used to change receiver variants. It's mainly intended for shops.

Home Videos About Buy Email