OpenGD77 support sending SMS in Hotspot mode?

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kt4lh
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OpenGD77 support sending SMS in Hotspot mode?

Post by kt4lh » Sat May 16, 2020 4:45 pm

I know it doesn't support it as a normal radio, but does it support it in hotspot mode? Was just messing around today trying to send some SMS with the GD77 as hotspot and my MD380 as the radio and everything always fails.

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F1RMB
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Re: OpenGD77 support sending SMS in Hotspot mode?

Post by F1RMB » Sat May 16, 2020 5:54 pm

Hi,
kt4lh wrote:
Sat May 16, 2020 4:45 pm
I know it doesn't support it as a normal radio, but does it support it in hotspot mode? Was just messing around today trying to send some SMS with the GD77 as hotspot and my MD380 as the radio and everything always fails.
Nope, it doesn't send SMS. As the core of the firmware don't support SMS, it simply can either.


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Daniel
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kt4lh
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Re: OpenGD77 support sending SMS in Hotspot mode?

Post by kt4lh » Sat May 16, 2020 9:39 pm

F1RMB wrote:
Sat May 16, 2020 5:54 pm
Hi,

Nope, it doesn't send SMS. As the core of the firmware don't support SMS, it simply can either.
Makes sense, wasn't sure if it was just going to be a blind pass-through thing or an active thing, thank you for the confirmation!

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Re: OpenGD77 support sending SMS in Hotspot mode?

Post by VK3KYY » Sat May 16, 2020 11:48 pm

The way Hotspot mode works in the GD-77 is totally different from the JumboSpot etc hotspots

The Jumbospot etc, are effectively just a dumb "pipe" which just decode the 4FSK signal to bytes and send the bytestream to MMDVMHost (and the same thing in reverse with the bytestream from MMDMVHost)

The GD-77 firmware does not have access to the 4FSK , it only has access to the fully decoded data in the DMR e.g. the ID's and TG's etc

So there is a large body of code in the firmware which has to construct the DMR bytestream from the ID TG and AMBE data etc etc.

A consequence of this, is that any data types like SMS which the firmware doesn't support, can't be handled by Hotspot mode.

Adding SMS support to Hotspot mode will be a difficult job, because the SMS protocol seems to be an undocumented Motorola standard on top of the DMR data transfer protocol.

Also, there does not seem to be any documentation in C6000 datasheet about even how to handle the DMR data transfer protocol.



BTW.

I read recently that in theory it's possible to access the "Physical layer" data for the DMR data inside the C6000, which would remove the need for a huge amount of the Hotspot code that creates the DMR byte-stream from the high level data.

However, the devil is in the detail, because there is no documentation on how to access the "physical layer" data in the C6000 either

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