Understanding Connect Plus trunking

[Forts]

At this point, I'm guessing it only shows the Network and Site ID for SLCO=10 messages. We will have to get Ian to add SLCO=9 as well. Best we can tell the messages are the same, but SLCO=9 would indicate a voice channel where as SLCO=10 indicates a control channel.

 

[Forts]

Group Address : 11919499 Source Address : 11910000

Don't ya love the Group addresses they pick on some of these systems? Some of the are pretty bizarre to say the least, but in your case it looks like they prefix the network ID (119) onto the group and radio ID's. Kinda smart for big systems.

 

[IanWraith]

Hello

Ian, while monitoring a voice channel, I logged this display. Does the Network ID (1110111 = 119) and Site ID only show up on the control channel?

No the program only decodes the SLCO=10 messages at the moment. I hadn't realised the SLCO=9 messages were the same but on the voice channel. I will add the decoding of these to another build next week all being well.

Regards

Ian

 

[inigo88]

Don't ya love the Group addresses they pick on some of these systems? Some of the are pretty bizarre to say the least, but in your case it looks like they prefix the network ID (119) onto the group and radio ID's. Kinda smart for big systems.

He and I are monitoring the same San Diego connect plus system. What's really weird is when I first started decoding it back before DMRDecode supported connect plus, the talkgroups were in 50xxx format. So over the last couple months they went back in and reprogrammed them all with the 119xxxxx format.

By the way so far the only site I've been able to find voice channels for is site 3, and so far I've only seen group 11919499 active also.

 

[IanWraith]

Hi Folks

I have just uploaded build 43 to Github which should also decode SLCO 9 messages. I would be grateful if someone could give it a test.

Regards

Ian

 

[Forts]

Wow, that was quick!

Slot Type : Colour Code 1 Idle
7:30:00 AM Short LC : Connect Plus Voice Channel SLCO=9 Network: 158 Site: 5

Works great, as usual! Thanks Ian!

 

[wa6yvx]

Excellent!

Slot Type : Colour Code 3 Terminator with LC
Group Voice Channel User LC
Service Options : Non-emergency/No priority
Group Address : 11919499 Source Address : 11910000
1:41:36 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

 

[inigo88]

Excellent!

Slot Type : Colour Code 3 Terminator with LC
Group Voice Channel User LC
Service Options : Non-emergency/No priority
Group Address : 11919499 Source Address : 11910000
1:41:36 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

Now you've got me excited! What frequency was that on??? So far I've only been able to find voice channels (SLCO=9) on Site 3. Here's what I was able to find while band-scanning 450 MHz - 470 MHz last time I ran DMRDecode (excluding the six site control channels):

461.6125 - Network: 119, Site: 3, Group: 11919499, Source: 11910000

463.6875 - Network: 119, Site: 3, Group: 11919499, Source: 11910000, 11910007

463.8250 - Network: 119, Site: 3, Group: 11919499, Source: 11910000, 11910014

The control channel for Site 3 is 454.5250. So I have gathered the following info on that site:

Network 119
Site 3

454.5250 - Control Channel
461.6125 - Voice
463.6875 - Voice
463.8250 - Voice

Groups: 11919499

Radios: 11910000, 11910007, 11910014

Per my previous post, the full list of control channels (since there can only be six) is:

454.0500 - Network: 119 - Site: 1
461.3000 - Network: 119 - Site: 2
454.5250 - Network: 119 - Site: 3
454.0375 - Network: 119 - Site: 4
463.4375 - Network: 119 - Site: 5
453.0125 - Newtork: 119 - Site: 6

Care to compare notes? What have you found so far? Care to venture any guesses on site locations?

 

[wa6yvx]

Site Info

Inigo,

Reference your site list, I see it as having sites 2 and 3 reversed. I'm also getting 454.5250 indicating site 3 with a Net ID of 119. I did a "scan search" between 451.0000 Mhz and 466.0000 Mhz and came up with 15 channels all using color code 3, thinking they may all be part of the Fisher system. When I verify them, I'll send you the list.

On a previous post, did you also indicate that there is voice activity also on the control channel?
(so far I haven't heard any voice on them so I've been mostly scanning the voice channels). Which appear to be some sort of a Transit System on most of them.

 

[Forts]

Timeslot 2 on the control channel is available for voice or data traffic. The control channel is always on timeslot 1.

 

[wa6yvx]

Multiple Site Channels

I guess there may be several channels at each site. This should be quite a puzzle to figure out which channels go to each site.

 

[Forts]

Not with the latest build of DMRDecode When voice channels are active it will show you which Network ID and Site ID that frequency belongs to.

 

[inigo88]

Inigo,

Reference your site list, I see it as having sites 2 and 3 reversed. I'm also getting 454.5250 indicating site 3 with a Net ID of 119. I did a "scan search" between 451.0000 Mhz and 466.0000 Mhz and came up with 15 channels all using color code 3, thinking they may all be part of the Fisher system. When I verify them, I'll send you the list.

On a previous post, did you also indicate that there is voice activity also on the control channel?
(so far I haven't heard any voice on them so I've been mostly scanning the voice channels). Which appear to be some sort of a Transit System on most of them.

My site list should be correct. Here's a list of the control channel frequencies with their corresponding SLCO=10 binary code:

454.0375     000001110111000001000000
454.0500     00000111011100000[B][U]001[/U][/B]0000
454.5250     00000111011100000[B][U]011[/U][/B]0000
461.3000     00000111011100000[B][U]010[/U][/B]0000
463.4375     000001110111000001010000
453.0125     000001110111000001100000

The above shows that 454.05 is Site 1, 461.30 is Site 2 and 454.525 is Site 3. However I haven't listened in a few weeks, so they may have been switched around.

I specifically wanted to ask you about this:

1:41:36 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

...Because that means you found a voice channel (SLCO=9) associated with Site 1. All the voice channels I've found (461.6125, 463.6875, 463.825) have belonged to Site 3. What frequency did you get that SLCO=9 site 1 message on?

 

[wa6yvx]

I've been doing all my monitoring at night, and there is little voice activity. When I get a chance during the day, I'll try and piece more together. I need to save my log names as a frequency, and not scan during that time so I can tell what data is on each freq. So I can't tell you which freq that SLCO=9
was on.

I'm was getting voice on 454.0375, but it is so close to the control channel of 454.0500 that it gets covered up on my old scanner. (BC780XLT)

 

[wa6yvx]

Here is what I got today on these 7 voice channels from sites 1,2 and 3. They all have the same group ID of 11919499.

452.36250: Group Address : 11919499 Source Address : 11910022
8:43:21 AM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

454.1750: Group Address : 11919499 Source Address : 11910000
3:15:17 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

454.5875: Group Address : 11919499 Source Address : 11910018
4:23:20 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 1

451.3250: Group Address : 11919499 Source Address : 11910022
5:48:38 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 2

464.6250: Group Address : 11919499 Source Address : 11910026
5:39:56 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 2

454.5875: Group Address : 11919499 Source Address : 11910018
5:03:37 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 3

463.8250: Group Address : 11919499 Source Address : 11910000
5:37:28 PM Short LC : Connect Plus Voice Channel SLCO=9 Network: 119 Site: 3

 

[inigo88]

Thank you VERY much. I'll throw those in my old discriminator tapped scanner and see if I can figure out who 11919499 is with DSD.

 

[wa6yvx]

Almost all of the conversations I've heard has been some sort of Transit company, maybe San Diego MTS (Metropolitan Transit System). Talking about routes, locations, vehicle conditions and wheelchair passengers.

 

[inigo88]

Almost all of the conversations I've heard has been some sort of Transit company, maybe San Diego MTS (Metropolitan Transit System). Talking about routes, locations, vehicle conditions and wheelchair passengers.

Based on what you're describing it could be the paratransit (wheelchair) bus component of MTS. MTS has a lot of little subsidiary companies that they contract out to, each with different radio systems. For instance San Diego Transit (SDTC) does most of the bus routes in the city and has its own "talk-permit" digital 800 MHz conventional system, so it can't be them. There were also a couple paratransit bus type companies on the RCS, so this could be an additional one or maybe one of the ones from the RCS bailed looking for cheaper rates?

 

[scannerfreak]

Out of nowhere I had one of these systems pop up recently. I first want to express my thanks to the author for this awesome piece of software and to all those who have posted here with info. Very well done. I am successfully using a PSR 800 to monitor the data output.

Now on to my first of probably many questions as I dive into this for the first time. I read the NID is an editable field in the CPS, do we know for certain if this is a unique ID? Are the installers assigning them at will, or are they following some list somewhere? My system is 163.

 

[Forts]

It looks like the NID can be edited in the CPS, but I've been told the ID is indeed assigned by Motorola.