DMR Cap Max Traffic Channel Audio Events Show Incorrect Duration

[DSheirer]

Describe the bug
When decoding a DMR Tier III Cap Max system the call events duration value is showing 0.0 or 0.1 seconds in length.

Additional context
Attached control channel bitstream recording for troubleshooting.

20240109_170914_420750000_9600BPS_DMR_DMR_Tier_III_Site_2_Control_7.bits.tar.gz

The attached example is for a DMR Capacity Max system operating in 'Advantage Mode' where (only) MotoTRBO radios can register on timeslot 2 to avoid contention on timeslot 1. Timeslot 2 can also be used for voice calls when the system doesn't have any repeaters available.

See conversation about 'Advantage Mode' vs 'Open System Mode' here:

https://forums.radioreference.com/threads/kenwood-and-tier-3-dmr.444052/

Tell-tale characteristic of a DMR Cap Max system operating in Advantage mode is the Aloha messages on timeslot 2.

[DSheirer]

Hello, The system I am monitoring is a Motorola DMR Tier III Capacity Max system and I listen to it

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Can you please make a bitstream recording, or a couple, of the control channel and send to me so that I can troubleshoot?
Denny

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Here is the demodulated bitstream (.bits)
Let me know if you need more data.
The system isn't very busy, the users of the system are the county fire dept and public works.
The group call does come in and I get voice but the duration and recording do not work. The duration of group calls will be 0.0 or 0.1 in length.

[DSheirer]

Looks like this system is employing RAS, or non-standard CRC initial fill values.

[DSheirer]

The recent PR implements an auto-correct feature for DMR CSBK (ie control) messages to detect when the DMR network is using alternate CRC mask values.

However, this change alone may not resolve the original reported issue where calls are not being correctly decoded and managed and this is reflected in the call event duration values.

The attached bitstream recording only contains control messaging and doesn't contain any calls. I'll need additional bistream recordings that contain calls to verify that the code fix resolves the issue.

[DSheirer]

The attached example is for a DMR Capacity Max system operating in 'Advantage Mode' where (only) MotoTRBO radios can register on timeslot 2 to avoid contention on timeslot 1. Timeslot 2 can also be used for voice calls when the system doesn't have any repeaters available.

See conversation about 'Advantage Mode' vs 'Open System Mode' here:

https://forums.radioreference.com/threads/kenwood-and-tier-3-dmr.444052/

Tell-tale characteristic of a DMR Cap Max system operating in Advantage mode is the Aloha messages on timeslot 2.

[DSheirer]

Additional recordings of traffic channels.

CapacityMaxAdvantageModeAdditionalExamples.zip