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[Sticky] FrSky RX4R Receiver

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Posts: 185
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frsky RX4RNew1 540x400

New to the X series range the RX4R boasting lower latency and improved range compared to the X4R

The RX4R is a standalone receiver with all the functions of X4R, it features 4 PWM outputs with high precision and low latency. The PWM output latency is 9ms less than that of the X4R in high speed mode. The RX4R also supports the redundancy function, this means you can add another receiver as a back-up in case the first one fails. Last but not least, the RX4R and the whole RX-line has a 40% increased operating range compared to the previous X series receivers.


  • Small and High sensitivity (40% increase of the range compared to previous X series receivers)
  • Higher precision PWM and Low latency PWM output
  • Lower power consumption
  • Redundancy function supported
  • Smart Port enabled and telemetry data transmission supported
  • Battery voltage detection supported
  • 2 detachable IPEX 4 connector antennas
  • PCB protection with the comformal coating craftwork


  • Dimension: 18×17×7mm (L×W×H)
  • Weight: 2g/ 2.4g (with two antennas)
  • Number of Channels:16CH (1-4CH PWM from conventional channel outputs, 1-16CH from SBUS OUT port)
  • Operating Voltage Range: 3.5V-10V
  • Operating Current: 100mA@5V
  • Operating Range: >2km
  • Servo Frame Rate: 9ms (HS—High Speed Mode)/18ms (FS—Normal Speed Mode)

All files relating to the RX4R Receiver including manuals and firmware updates can be found here:

Posted : 11/04/2019 11:44 am
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Hi all--  I'm just setting up my first Taranis X9D+ 2019 with several rx (RX4R, Rx6R and G-RX6R) with ACCESS protocol over Open-Tx v2.3.7 and V2 firmware on RX4R and other rx.  Everything is talking to each other - so far, so very good (although I'm glad I worked in IT for several decades!)  ????

But three questions if I may:

1.  I read in an earlier R-XSR thread that RSSI alarm levels should be reduced for ACCESS (under OTX v1.1.3) protocol to Low=35 and Critical=32.  Do the reduced alarm levels apply to the RX4R and other Rxs too on the latest software releases?  The alarms were set on delivery (under v1.1.3) to L=45, C=42. 

2.  Can you tell me what the RX4R A2 telemetry signal represents with nothing connected to the AIN2 pin?  The reading comes through as about 11.7V (though I'm running on a 4.8V rx battery!) - is that just a floating-pin value?  I've not tried grounding the pin yet.  

3.  Do the two jumpers included with the rxs have a purpose?  

I couldn't find answers in the docs or on

Thanks --Pete

Posted : 28/04/2020 11:22 am
Posts: 185
Reputable Member Admin
Topic starter

Yes lower the levels as described in the previous thread mentioned.

I am sorry, I don't know the answer to your second question

The jumpers are used on the ACCST version firmware to select either HS or HF mode.  I suspect the jumpers are included with both ACCST and ACCESS because you can flash it with either firmware.


Hope some of this is helpful.

Posted : 30/04/2020 12:46 pm
Pete reacted
Posts: 11
Active Member

Thanks Cliff it's all helpful.  I eventually found the guidance on the RSSI alarms later in the X9D manual too.  Not tried grounding the A2IN pin yet in gliders but the system doesn't seem to mind!

Posted : 02/05/2020 1:59 pm
Posts: 2
New Member



I'm trying to setup my Elf DLG (Rudder + Elevator) on my X9D Plus. I flashed the RX4R with ACCST firmware as my radio isn't ACCESS compatible, and I've managed to bind it. However only my rudder servo (Ch. 4) has output. I've no output on elevator servo. If I go into radio settings, I can see that the model is setup for channels 3 and 4 and I'm wondering if this is potentially a duff receiver.


Any thoughts?


Thanks in advance,



Posted : 14/05/2021 10:51 am
Rich bago
Posts: 96
Estimable Member Admin Registered

try swapping to the other channels 1 and 2 see if kicks into life

Posted : 14/05/2021 12:39 pm
Posts: 2
New Member

@richbago thanks. Do you mean swap in radio model setup or physically swap the servo connectors on the Rx?

Posted : 16/05/2021 11:36 am