DSDPlus DSD - DMR PDU usage when FID not 0

thewraith2008

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Nov 22, 2016
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Hi,

I've been playing around with the code in DSD 1.7 adding a fair bit of the code required to poke around with the layer 2 and 3 PDUs in DMR.
I was wondering when the FID is not 0 (e.g. 16, 88), does the description for the known opcodes for CSBKO or FLCO remain the same with the elements/structure of the PDU is that differs?

e.g.
FLCO: 8 with FID: 0 is defined in the standards as 'GPS Info'.
If the FID is 88, will this still be for 'GPS Info' just with different elements/structure or is it something different?
 

slicerwizard

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I would say that when a PDU contains a manufacturer's FID, such as 16 (Motorola), 88 (Tait), etc., there's a reason, i.e. the data isn't going to match the standards.
 

thewraith2008

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So do you think that the purpose of the PDU is still going to be the same, e.g. FLCO: 8 as 'GPS Info' regardless of FID.
 

DSheirer

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I haven't (yet) encountered any vendor-specific implementations where they repurposed the FLCO to mean something else. There's generally enough address space available in link control opcodes that they shouldn't have to use an opcode to mean something else.

Did you encounter a custom Tait GPS FLC?

Denny
 

thewraith2008

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Hi Denny,

I was guessing that was the case.
Knowing what a PDU is for (with non 0 FID) can maybe help add context to the data been looked at and hopefully be able make sense of it.

While I do see FLCO:8 - FID:88 (Tait) in use, it was only used here as an example.
I have not yet started to investigate the contents of the data other than to know it is different. So far the work I have done is to add FEC/EDC, PDU processing and some basic trunking capability into my DSD.

Thanks for the reply.
 

thewraith2008

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Nov 22, 2016
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Yeah I think for the time being I'll side step playing around with these PDUs.
Plenty of other areas to play around with and I know some of these have been partly defined by other DSD/DMR projects that exist out there.

Thanks for the reply.
 
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