RFD Modem Types Explained - Just FYI


900 vs 868

This indicates the frequency ISM frequency bands that the modems are intended for in MHz. Modems of different frequency bands cannot interoperate.

+, u, X, uX and uX-SMT

+: The + models are an update with some minor improvements of the very first RFD modem designs. They can interoperate with the original modems and u modems of the same band. This product is maintained for legacy systems but is not undergoing active development and updates.

u: The u models are a small light modem for use in situations where size and weight are critical. These modems have a reduced maximum power of 20 dB but otherwise all the same features as the + models.

X: The X models an newer design with a new processor and added features over the + and u models such as RC and S.Bus pass through and GPIO pin mirroring with ongoing improvements. This is the model integrated in to other RFD products such as the TX Mod. They cannot interoperate with older modem types.

uX: The uX is a size and weight reduced version of the X modem. It has a limited number of GPIO pins but otherwise operates the same as the X model. Unlike the u model this modem is capable of the full 30 dB output power.

uX-SMT: The uX-SMT models are solderable surface mount modem for system designers wanting to integrate RFD modems into custom electronics solutions. All GPIO and UART functions are available as the solder pads. The software functions are identical to and interoperable with X and uX models.

Country Codes (-AU etc)

The -XX country codes after X, uX and uX-SMT models indicate modems that have been locked for compliance with different countries regulations. These modems may have some features or options removed and are not compatible with all firmware types. New variants may be added in the future.

Country codes.

AU: Australia

NZ: New Zealand

US: United States of America (also applies to Canada)

EU: European Union

IN: India

Modem and Firmware Datasheets

Modem and firmware datasheets for our various products can be found at the following link.



And downloads of firmware and tools are in that URL too:

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Yes…RFD modem is a great company. Love their products!!

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Good to see some more compact modems. Loving the Ux! Just need a can bus version now :grin:

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I have asked Mortem owner to see if he has any plans of developing a CAN version. Lets see what he comes back with.

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On my HexSoon450 I have the 868 with Mod on the radio it is one great bit of kit the very best in fact

Is 868 better than 900x? And why?

They should perform nearly the same. The reason for this two frequencies is the different regulations in different countries.

Same with the Telemetry radios where a 433Mhz and a 915Mhz variant exists. 433 is for Europe, 915 for USA

If you used 915Mhz in Europe you would be broadcasting on the same frequency as mobile phones

That’s what I thought. Marty lives in the US I think, so i got confused why is he using 868…

Asim and Vabe, I stay in Scotland,and 868 is the legal one here

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ah…Whit’s fur ye’ll no go by ye! :slight_smile:

One of my old Boss was from Scotland…very funny guy…

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that is a very true saying and were built from girders,lol

Awk eye thee noo

I did a 60 day tour last year from Portugal all the way to Austria and all the countries in the middle. Love European chill lifestyle.

One of my hardware design engineer is in Ireland (Dublin). I was planning to visit Ireland and Scotland this year, but this dang coronavirus screwed things up. Hopefully next year.

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Asim,you will really love both Ireland and Scotland though you may suffer from a few hangover’s,lol

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lol…I know, in Germany I had, I think like 18% Alcohol Beer…you guys can drink anyone under the table for sure… ha ha

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Dont no if that is a good thing or not

Thats why at the bottom of every beer bottle it says, “Please open the bottle from the other side” :slight_smile:

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As we say here,be in good spirit’s not full of it