Author Topic: DMR Simplex Modes Tested  (Read 111 times)

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Offline VE3RD

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DMR Simplex Modes Tested
« on: October 21, 2023, 03:14:24 pm »
DMR Simplex Modes

The Anytone D878UV Plus and The Anytone D878UVII Plus both have the following options for setting a simplex channel.
DMO/Simplex
DCDM TS Split
DCDM/Double Slot


Radio 1 - Anytone D878UV Plus
Radio 2 - Anytone D878UVII Plus
Both radios on the same simplex frequency

DMO/Simplex (the most popular mode I see in use)
Tests Done in DMO Mode indicate that regardless of what is selected for transmit either TS1 or TS2, the other radio will converse with it on either TS1 or TS2
ie: Radio 1 TS1 communicates with Radio 2 TS2 and reverse is also true.
To me this indicates that the receiver is listening to both time slots and locks into the one received, and the other goes idle.
Example: Radio 1 TS1 to Radio 2 TS2. Radio 2 hears Radio 1 on TS1 and opens the receiver. Radio 2 transmits back on TS2 which Radio 1 hears on TS2 and opens the receiver.
So in this regard both Time slots are used, but only one at time. If Both radios are on one Timeslot then only that one timeslot is active.

Think of a DMR Simplex Hotspot in DMO/Simplex  Single Frequency Mode set on TS2 with one exception.
There is code in MMDVMHost that drops TS1 packets if the hotspot is not in duplex mode.



DCDM TS Split
Radio 1 TS1 will not communicate with Radio 2 TS1(EH?)
However it will communicate with Radio 2 on TS2.
This mode might be useful for a master to talk to a bunch of slaves which cannot communicate with each other
I suspect that Radio 1 TS1 is transmitting on TS1 and listening on TS2 while Radio 2 TS2 transmits on TS2 and listens on TS1

DCDM/Double Slot (My TYT MD390UV has this capability - but not tested)
Radio 1 TS1 will communicate with Radio 2 TS1
Radio 1 TS2 will communicate with Radio 2 TS2
Radio 1 TS1 will NOT communicate with Radio 2 TS2
Radio 1 TS2 will NOT communicate with Radio 2 TS1

The MMDVM Host log file shows no activity when DCDM Double Slot TS1 is used.
MMDVM does pass on traffic to TGIF when DCDM Double Slot TS2 is used.
In DMO/Simplex Mode MMDVM will pass all TS1 traffic as TS2

I am no expert on this stuff by any means, This is just a result of testing the indicated modes on my two D878 Radios
I will leave it up to the experts to explain what is actually happening under the covers so to speak.

Phil VE3RD
« Last Edit: October 27, 2023, 07:13:56 pm by VE3RD »

 

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