In this article, we are going to compare ACCESS and ACCST Frsky Protocols and to find out If it is really worth to upgrade your radio. If you are a Frsky user in the past few years, then you probably might have come around the term ACCST, which stands for Advanced Continuous Channel Shifting Technology and that is the protocol used by Frsky in their Radios in the past few years. Now Frsky has released another Protocol, ACCESS, which stands for Advanced Communication Control Elevated Spread Spectrum that only supports the newly Released Taranis and Horus Radios. 

 What is Protocol


               You need to understand what is a protocol and how it differs from Firmware in order to best understand this article. Firmware is a piece of code or program that runs in the Transmitters and Receivers and that is what it enables to communicate with each other. Where Protocol is a set of rules for data exchange or communication. A firmware alone cannot allow these Transmitters and receivers to communicate with each other, But it requires a protocol that will control How and when these should communicate.  

               Each Manufacturer Uses different Firmwares and Protocols in their Transmitters and Receivers and that is what makes them unique. A protocol can be referred to as a key or a password in communication between the Radio and receiver and anyone who can decrypt the protocol can replicate or Design such receivers as the Firmwares are already available in their Authorized Websites. For the same reason, Manufactures encrypt or add security layers in order to protect their protocol from 3rd Party to steal it and design compatible receivers for such transmitters.




               ACCST Frsky protocol stands for Advanced Continuous Channel Shifting Technology Frsky is a very old protocol used by Frsky in their Taranis and Horus Radios like Qx7, X9d, etc. It used D8, D16 and LR12 Modes to Bind with the Receivers. So you have to choose these modes and sometimes it will be frustrating to find out which mode is required to bind with the Radio. 

               The maximum number of Channels that ACCST can output is 16 in Sbus and 8 in CPPM Mode. The ACCST protocol was reverse-engineered by 3rd Party Developers to make compatible Receivers. That is why you can see there are several 3rd Party Frsky Receivers even integrated with Tiny Whoop Flight Controllers. Is that Why Frsky has come up with the latest ACCESS Protocol to prevent third parties from making Frsky Compatible Receivers? Or are there other worthy Benefits in the new Protocol?



               ACCESS is the latest Protocol released by the Frsky for their Newly Released Radios Like Xlite Pro, X9 Lite, XD9 Plus 2019, etc. ACCESS Stands for Advanced Communication Control Elevated Spread Spectrum and it comes with many amazing features and improved performance that make it very tempting to upgrade the radio. We are going to discuss the features one by one below. 


               More Number of Channels

               The maximum number of Channels that ACCST Frsky protocol can output in Sbus is 16, But ACCESS has an output of 24 Full Range Channels in Sbus. Even though People Don’t use more than 10 Channels in most scenarios. 

               Improved Latency

               Latency is the short delay in reaching the signal from one point to another and the delay in processing the signal by the receiver. Even though it may be only a few ms, But it matters a lot in Drone Racing where quick responses and sudden Maneuvers are performed. Therefore, Each Milliseconds counts in Drone Racing and you need the minimum latency as possible. 

               Latency Increases when the number of Outputting Channels increases. That Is why most users limit the number of channels in the radio settings to 10 or 8 Depending on the number of Auxillary Channels they require. ACCESS Firmware has the minimum latency when compared to ACCST Firmware. Below you can find the average Latency compared to the ACCST Frsky Protocol and the latency results are really Amazing.



Average Latency

(8 Channel)

Average Latency

(16 Channel)

Average Latency

(24 Channel)

X-lite Pro ACCESS




Qx7 FCC (with Heartbeat) ACCST




Qx7 FCC without Heartbeat ACCST





Smart Match

               Smart Match is the Wireless Binding of Receivers to the radio without pressing the F/S Button. Now Binding to your model is more secure than ever before. Once a Reciever is Registered to a Radio, You can wirelessly bind the receiver without ever touching it. You only need to register the receiver for the first time, which is similar to Binding the Reciever. But once you did it, you can bind the receiver again and again without ever touching the receiver again. Isn't it a cool Feature?


OTA Update

               OTA or Over-The-Air Update is an amazing feature that lets you wirelessly update or upgrade the firmware in the receiver and you don’t need to bind it again with pressing the F/S Button. Now Firmware updation in the Radio has been easier than ever before


Spectrum Analyzer

You are now able to use your transmitter to survey the airwaves, which can measure your signal strength and others in your area. The Spectrum Analyzer allows the user to measure the noise, and distortion of the frequencies around.

Advanced Encryption Algorithm

               Frsky claims that higher encryption will provide more peace of mind that your model signal will not be interfered with. But it may be to Prevent 3rd Party Developers from Making Frsky Compatible Receivers


Trio Control

               With the ACCESS firmware, you are now able to configure telemetry for up to 3 Receivers simultaneously through the radio. You no longer need to use STK tools and Smart Port allows the use of third-party input/output devices with pass-through mode.



ACCESS Firmware has more advanced and cool features that make everything more simple and user friendly. Therefore It is worth upgrading to an ACCESS radio. But it would have a lot easier if Frsky could release ACCESS firmware for the ACCST Frsky Transmitters. Because users may not want to spend another 100 or 200 Bucks to Upgrade to an ACCESS Radio. Perhaps, there might be some hardware Incapability. I hope this article has helped you to learn the ACCST and ACCESS Protocols of Frsky.