Understanding Capacity Plus trunking

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Forts

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Just thinking out loud.... before we branch off too far discussing RAS should it maybe be moved to a new thread?
 

EricCottrell

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Can you tell me which PDU this appears in ?

Thanks

Ian

Hello,

csbko 62 FID 16
bits 20 - 23 Rest Channel
bit 24 Channel 1 Active
bit 25 Channel 2 Active
bit 26 Channel 3 Active
bit 27 Channel 4 Active
bit 28 Channel 5 Active
bit 29 Channel 6 Active
bits 32 - 39 Talkgroup on lowest active channel number
bits 40 - 47 Talkgroup on second lowest active channel number
bits 48 - 55 Talkgroup on third lowest active channel number
bits 56 - 63 Talkgroup on fourth lowest active channel number
bits 64 - 71 Talkgroup on fifth lowest active channel number
bits 72 - 79 Talkgroup on sixth lowest active channel number

Example:
if bits 25, 27, and 29 are set, then bits 32 - 39 represent the talkgroup on Channel 2, bits 40 - 47 represent the talkgroup on Channel 4, and bits 48 through 55 represent the talkgroup on Channel 6.

73 Eric
 

EricCottrell

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Hello,

I got suprise tonight while listening to a busy 4 repeater system at TD Garden.

csbko 62 FID 16
bit 30 Channel 7 Active
bit 31 Channel 8 Active

Unfortunely I only got a peak of five active talkgroups so far.
Slot 0 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot A ?:0 RCh: 2 ACh:1 3 678 TGs:6E 6F 72 69 6C
Slot 1 CC: 1 TLC pf:0 Grp V Ch Usr Grp:0x000072 RId:0x0027A9
Slot 0 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot A ?:0 RCh: 2 ACh:1 3 678 TGs:6E 6F 72 69 6C
Slot 1 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot B ?:0 RCh: 2 ACh:1 3 78 TGs:6E 6F 69 6C
Cach: SLCO:15 100200
Slot 0 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot A ?:0 RCh: 2 ACh:1 3 78 TGs:6E 6F 69 6C
Slot 1 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot B ?:0 RCh: 2 ACh: 3 78 TGs:6F 69 6C
Slot 0 CC: 1 CSBK lb:1 pf:0 MtCap+ GoTo ?:3 Slot A ?:0 RCh: 2 ACh: 3 78 TGs:6F 69 6C

Since there can be up to 6 repeaters (12 channels), there has to be a bit or another message to indicate the 7th through 12th active talkgroup and to handle Channels 9 through 12 being active. The TD garden is the biggest system I have found so far.

73 Eric
 

Forts

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There is a University about an hour from me that has a 5 repeater system. I'll see if I can get over that way sometime soon a do a little logging.
 

IanWraith

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Example:
if bits 25, 27, and 29 are set, then bits 32 - 39 represent the talkgroup on Channel 2, bits 40 - 47 represent the talkgroup on Channel 4, and bits 48 through 55 represent the talkgroup on Channel 6.

73 Eric

Thanks for the info Eric. I have put this info into DMRDecode as comments ..

https://github.com/IanWraith/DMRDecode/commit/1b6de567bc10e3a0719c35ecac9318ebc9b2577e

for now as I am rather busy. But when I get a little time I will add this as Java code then test and release a new build.

Many thanks for all your help with this and you will see you are credited in the DMRDecode source code and in the Github commit.

Regards

Ian
 

inigo88

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EricCottrell

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There is a University about an hour from me that has a 5 repeater system. I'll see if I can get over that way sometime soon a do a little logging.
Hello,

I noticed a recent RRDB update where Mohegan Sun Casino went from a 12 channel MPT-1327 to Mototrbo. The database had it as a three site Linked Capacity Plus system. I checked it out and it is really a three site Connect Plus system. :( One site is using 12 repeaters, yes, 23 voice channels! All the talkgroups I received were encrypted. I submitted the correction.

73 Eric
 

M0DQO

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Hi all,

Just wanted to see if any of you have experienced the following when monitoring a capacity plus system?

I have a local Pub/shopwatch system that I believe has a pool of three frequencies, on colour code 3 as they are all registered to the same owner. However, each of the three frequencies has different users and user groups operating on it, but they users are never on the other LCN's at anytime I've monitored them?

For example, the city centre groups always stay on LCN4/5 and I have never seen a different rest channel other than 5 or 6? The other users stay on LCN3/4 with exactly the same scenario? Is this a badly configured system or can you restrict what groups have access to what trunks somehow?

The channel is active all day with beacons and calls bouncing between LCN5/6 and not as I would expect from a 6 slot trucked system!

Just wondered of anyone has ever experience this before while monitoring other systems as I thought I had three systems I was looking for associated trunks.. I am convinced that it's the same system as I cannot find any other code 3 repeaters or signals elsewhere?

Thanks in advance

Chris
 

EricCottrell

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Hello,

Reading other patent information turned up two new sync patterns that are used for both Time Slot 2 in Direct Mode and for the Rest Channel in a trunked system. I need to try out these patterns and see if it improves the sync on the Rest Channel.

#define DMR_BS_DATA_REST_SYNC 313113333311311311133131
#define DMR_BS_VOICE_REST_SYNC 131331111133133133311313

73 Eric
 

EricCottrell

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On the LCP system that I am monitoring, I get the following:
CSBKO=59 + FID=16 1110011100011011000100100010001001000011000000000000000000000000
and
CSBKO=59 + FID=16 1100011100011011000100100010001001000011000000000000000000000000
as a pair every 15 seconds. Then both repeat individually every 10-15 seconds. TT

Hello,

US Patent 20130122899 gives information on CSBKO=59 + FID=16. It is Adjacent Site Rest Channel information.
https://www.google.com/patents/US20130122899

CSBKO=59 + FID=16 11 1 00111 0 0011 011 0001 0010 0010 0010 0100 0011
First/Last Block
Slot = 2
Rest Channel = 7
Synchronized Beacons
This Site ID = 3
Number of Sites Listed = 3
1st Site ID = 1 Rest Channel = 2
2nd Site ID = 2 Rest Channel = 2
3rd Site ID = 4 Rest Channel = 3

73 Eric
 

Forts

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That's some excellent info you are digging up Eric, it will be a great addition to DMRDecode. Thanks for spelling it all out here!
 

EricCottrell

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Hello,

I searched around for EDACS patents several years ago and they gave some clues to various features. So I realized that a search for DMR stuff might also yield some useful info.

It appears the additional sync patterns for DMR are not implemented. This does not surprise me because there was stuff in the EDACS patents that were never implemented.

One open question is the format of the first/last field. A value of three means it is a single frame (first and last). I wonder if a value of one means first frame, a value of two means last frame, and a value of zero means a continuation frame. A dump from a five or six repeater Capacity Plus system would be a help to figure this out.

73 Eric
 

Forts

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When you say a dump do you just want logs from DMRd? If so I have 2 Capacity Plus systems near me that I can capture... And I will be in Toronto for a few days next week and can log some systems there.
 

IanWraith

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Firstly my thanks to Eric for all of his superb information recently. I would have thanked him sooner had I not been so busy recently.

Currently I'm working on the next build of DMRDecode which adds mobile and direct mode support to the program. I'm going to get that out then add all of Eric's Capacity Plus information.

Thanks again

Ian
 

M0DQO

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It would appear that a capacity plus system can have different colour codes per trunk as I've now cracked the system I was trying to monitor by decoding the three frequencies together and watching the LCN's change between the three repeater.. Maybe someone was giving me a call when they are CC's 2,4,6 in trunk order :)
 

Jay911

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I was about to come ask that because I have a city near me that is using 3 formerly-separate frequencies as an apparent cap plus trunk and the CCs were 6, 8, and 12.
 

M0DQO

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Cheers Forts, I just assumed that had the same colour code on all trunks! Makes tracking the larger systems down slightly more challenging!

Thanks,
Chris
 
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