FrSky telemetry mod without RS232 level converter

All mods related to the frsky telemetry series of the firmware
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bob195558
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FrSky DJT Telemetry Mod, without RS232 level converter

Post by bob195558 »

burbulence wrote: Fri Aug 04, 2017 10:13 am I have a DJT module with this modification without the level converter in my 9x modded to receive the FrSky telemetry on screen which works perfectly.
Ive just purchased the Taranis which now has this ridiculous EU LBT restriction on it so the internal XJT will not communicate with my older D or V series receivers.
Is it possible to use the external DJT module in the Taranis so I don't need to upgrade all my receivers straight away ?
Also if the module is safe to use is it also possible to display the D series telemetry on the Taranis also.
Thanks for any advice.
Hi burbulence,
Yes, when using erSky9x on Taranis firmware you can set an external DJT module to use PPM protocol
and make a cable to connect externally the Telemetry from com2. (http://www.er9x.com/)
I use for more flexibility the XJT module and by changing the dip switches you can change the XJT into a DJT module.

See here about making the Telemetry Cable: (viewtopic.php?f=96&t=4393&start=60#p79427)
and here about erSky9x on Taranis: (viewtopic.php?f=7&t=4582&start=150#p94504).

Also some more info when using erSky9x on Taranis with XJT and DJT modules
with telemetry connections and settings: (viewtopic.php?f=7&t=4582&start=150#p94519).

I have always used the external telemetry cables, so I am not sure when using the external DJT module
when using PPM protocol, works with internal telemetry connections.

FrSky external DJT module Mod for internal Telemetry connection
(this mod makes it safe to use in the Taranis): (viewtopic.php?f=95&t=3868&p=57121&hilit=#p57047).

Bob B.
Last edited by bob195558 on Fri Aug 04, 2017 9:26 pm, edited 5 times in total.
Er9x on 9x radio, with Smartieparts Programmer and TelemetrEZ Board.
ErSky9x on Taranis, Sky9x, 9Xtreme radios.
3D-Printing: (https://openrcforums.com/forum/viewforum.php?f=129).

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MikeB
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Re: FrSky telemetry mod without RS232 level converter

Post by MikeB »

When you download openTx, isn't there an option to tick/untick that enables/disables the EU option?
The XJT itself, even with EU firmware on it, still works with "D" and "V-II" receivers.

A DJT modified in the way you describe won't work for telemetry on a Taranis with openTx. With ersky9x firmware on the radio, it will work as I have a software driver that handles the non-inverted telemetry signal.

Mike.
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jhsa
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Re: FrSky telemetry mod without RS232 level converter

Post by jhsa »

Mike, what about the levels, would they be ok?
I didn't answer earlier because I wasn't sure about this, and didn't want to give an answer that could damage his module..

Thanks

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Re: FrSky telemetry mod without RS232 level converter

Post by MikeB »

A DJT modified for use without the RS232 level converter output 0-3.3V only, so works fine from that point of view. The Taranis needs to see inverted serial on the SPort connection and on the serial port on the battery bay.

Mike.
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Matevz25
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Re: FrSky telemetry mod without RS232 level converter

Post by Matevz25 »

Hi all! One question. I have taranis and with internal modul I get low rssi after 300 m or less. With 9x and djt modul mod done It worked a lot better. If I put djt modul to taranis do I need external wires for telemetry or it works with djt telemetry mode done for 9x? What settings do I choose for external module? Seams like eu firmware is less efficient. But I have it set on america and I can use d4r-ii reciver with it. Thanks!

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Re: FrSky telemetry mod without RS232 level converter

Post by MikeB »

If you have done the DJT mod that doesn't use the level converter then the telemetry won't work in a Taranis as the Taranis expects inverted data on both the SPort signal and on the serial port in the battery bay.
If you have the Telemetry mod that expects a level converter (which also inverts the signal), then see this post: viewtopic.php?f=95&t=3868&p=58136&hilit ... tky#p57047, for where to add a schottky diode to make the DJT compatible with the Taranis.

Mike.
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Matevz25
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Re: FrSky telemetry mod without RS232 level converter

Post by Matevz25 »

Hi Mike, yes was without rs232 mod. I have updated to latest non eu xjt firmware by simply remamed firmware file and tanaris exepted update. Now its a lot batter. So I am using external modul from turnigy 9x. Now I have all my planes and drone covered wth one tx. 😀. Later on I will use djt modul for backup for bigger planes. For 30cc plane witch is most expensive from all my planes I dont need it for now.Thank you for info.
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Re: FrSky telemetry mod without RS232 level converter

Post by dansleeth »

Sorry to chime in, but I see somebody recently resurrected this thread...

I attempted the telemetry mod for my XJT/TH9X using this method: https://oscarliang.com/turnigy-9x-advance-mod/

The radio still works fine, but telemetry data shows zero for Rx and Tx (basically it gets no data). I have not done any modification to the module itself, just re-routed the processor pins (with 220 resistors) and isolated/rerouted pin 2 and 5 on the back board.

Do I need to create the inverter for my setup? Does the protocol need to be set to PXX instead of SBUS? Do I need to remove the USB board used to flash firmware in order for this mod to work?

Any answers are greatly appreciated, as I am a little stuck with finding out where I went wrong... :?:
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Re: FrSky telemetry mod without RS232 level converter

Post by MikeB »

Yes, you need an inverter, the XJT output on pin 5 is inverted.
You also do need to set the protocol to PXX.
You shouldn't need to remove the USB board (which board are you using?).

Mike.
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