If you are a long time Frsky user, you probably recognize the word “ACCST” printed at the bottom left of the Taranis display. ACCST is a TX protocol and it will be soon be replaced by a new protocol – ACCESS.
What is ACCESS Protocol?
ACCESS stands for Advanced Communication Control, Elevated Spread Spectrum. It’s the RF protocol that carries the signal from the radio to the receiver, what I would normally call the air protocol or TX protocol.
The predecessor of ACCESS is ACCST, which has been around for over 10 years. You can find the ACCST label at the bottom left of Taranis X9D+ display.
I will discuss the new features and performance improvements that ACCESS will bring to the table.
Performance improvements from ACCESS include:
- Lower latency and higher baud rate
- Supports Up to 24 full range channels
However receiver protocols such as SBUS and FPort can only handle 16 channels, so I am not sure if there will be changes to the receiver protocols as well, or it requires multiple receivers to support the remaining eight extra channels.
Just like SBUS, using higher number of channels will increase latency just like SBUS. Currently with SBUS, we prefer to use 8 channels instead of 16 for the lower latency. We don’t normally need that many channels for flying FPV quadcopters anyway, so 24 channels isn’t really necessary. But the lower latency will certainly be appealing.
Wireless Binding and Firmware Updating
ACCESS allows you to bind and flash new receiver firmware wirelessly.
Once you register a receiver with the radio, you can bind it wirelessly without touching the receiver ever again (or press the bind button). Even after updating the receiver firmware. How is how to bind/register an ACCESS receiver.
I found this to be one of the most exciting new features. TBS has been doing this on the Crossfire for years and I am glad Frsky is finally catching up! Frankly, currently flashing new receiver firmware to Frsky receivers via smartport isn’t the most user friendly, hopefully the wireless method would make it a lot easier.
ACCESS has more advanced encryption according to Frsky. Not a huge concern for hobbyists to be honest, but it’s a good thing nonetheless
I also have a feeling that this is a move to make it harder to reverse engineer their protocol, to stop 3rd parties making compatible receivers and transmitter modules that compete with Frsky. For customers it’s not necessarily good news, as there will be fewer affordable options.
Backward Hardware Compatibility
As far as I know, ACCESS will be supported on some of the existing Frsky receivers, you would just have to flash a new firmware to support ACCESS. However you would have to purchase a new radio to use ACCESS, I don’t think older ACCST radios will support ACCESS.
You will need one of these radios Frsky recently released:
ACCESS firmware for receivers are already available for download on Frsky’s website, but only for five receivers at the time of publishing (May 2019): RXSR, RX6R, RX4R, G-RX6 and G-RX8.
For more info: https://www.frsky-rc.com/frsky-advanced-communication-control-elevated-spread-spectrum-access-protocol-release/