Unidentified TGs

Come here to talk about the San Diego and Imperial County Regional Communications System. This is a great resource to share talkgroups and information about the countywide RCS.
N6ATF
Posts: 373
Joined: Sun May 15, 2005 1:36 pm

Unidentified TGs

Postby N6ATF » Sun Feb 25, 2007 11:38 pm

not listed on
http://www.scandiego.com/rcs/RCS%20MAST ... KGROUP.htm

3584 even
4467 not
20480 even
6444 not
7558 not
6275 not
6274 not
24597 not
6307 not
11573 not
24981 not
12310 not
12288 even
12292 not
18968 not
12806 not
6446 not

That's all for now... seems like that list needs an official update.
Last edited by N6ATF on Mon Feb 26, 2007 10:34 pm, edited 1 time in total.

w6pix
Posts: 338
Joined: Wed Dec 31, 1969 4:00 pm

Postby w6pix » Mon Feb 26, 2007 9:33 pm

Many of those are not valid /\/\otorola TG ID's..

Divide by 16 and if it's even, then it's valid.

Otherwise, they indicate you were hearing either a resultant patch ID(status bits) or a data error of some kind.


Sean

N6ATF
Posts: 373
Joined: Sun May 15, 2005 1:36 pm

Postby N6ATF » Mon Feb 26, 2007 10:37 pm

A lot of those then. Frickin annoying.

So only 3 aren't listed: 3584 20480 12288

SkipSanders
Posts: 168
Joined: Sun Dec 03, 2006 10:12 pm

Postby SkipSanders » Tue Feb 27, 2007 5:23 am

Here's the info on Status Bits and 'Talkgroups' on scanners. There's usually a way to tell your scanner to ignore status bits, and display only the 'base' talkgroup.

It looks to me like the Radio Shack (GRE) scanners all show only the base talkgroup, while at least some of the Uniden scanners allow you to select whether to show only the base, or show the final status bit changed value instead.
------
Status Bits

Type II Smartnet systems uses status bits for special transmissions such as Emergency, Patches, DES/DVP scrambled transmissions, and Multiselects on Motorola Trunking systems. Motorola Trunking radios directly interpret them for their special functions, thus no difference is noticed by the person with the radio. The Trunktracker scanners however interpret these special talkgroup status bits as different talkgroups entirely. Below is the conversion chart for these special status bits.

Dec ID + # Usage
-------------------------------------------------------
ID+0 Normal Talkgroup
ID+1 All Talkgroup
ID+2 Emergency
ID+3 Talkgroup patch to another
ID+4 Emergency Patch
ID+5 Emergency multi-group
ID+6 Not assigned
ID+7 Multi-select (initiated by dispatcher)
ID+8 DES Encryption talkgroup
ID+9 DES All Talkgroup
ID+10 DES Emergency
ID+11 DES Talkgroup patch
ID+12 DES Emergency Patch
ID+13 DES Emergency multi-group
ID+14 Not assigned
ID+15 Multi-select DES TG

Therefore, if a user was transmitting a multi-select call on talkgroup 1808, the trunktracker would actually receive those transmissions on 1815. Some common uses of these status bits are as follows:

When a user hits their emergency button, all conversations on the talkgroup revert to the emergency status talkgroup (ID+2) until the dispatch clears the emergency status. Therefore, if someone hit their emergency button and their radio was on talkgroup 16, all communications would switch to talkgroup 18.

A lot of Fire and EMS departments dispatch tone-outs and alarms as Multi-select communications (ID+7). Therefore, if your fire department dispatch talkgroup is 1616, and they do dispatch tone-outs and alarms as Multi-selects, then those communications will be on talkgroup 1623.

This can be a problem, because you will miss communications if you don't have those talkgroups programmed. By setting the Type II block you are monitoring with a fleetmap of S-1 (Mot Size A), you'll essentially get Type I subfleets for each Type II talkgroup - encompassing all of the status bits into one subfleet. Some scanners also allow you to disable the status bit information so that you will alwys see the ID+0 regardless of the status of the talkgroup.
------

N6ATF
Posts: 373
Joined: Sun May 15, 2005 1:36 pm

Postby N6ATF » Tue Feb 27, 2007 10:04 am

No status bit option on my scanner. Guess I'm stuck.

SkipSanders
Posts: 168
Joined: Sun Dec 03, 2006 10:12 pm

Postby SkipSanders » Tue Feb 27, 2007 12:15 pm

Which scanner would that be? The ones that don't allow you to set it, normally only show the base group anyway. (So's I can check the manual on it)

N6ATF
Posts: 373
Joined: Sun May 15, 2005 1:36 pm

Postby N6ATF » Tue Feb 27, 2007 4:10 pm

See my sig?

SkipSanders
Posts: 168
Joined: Sun Dec 03, 2006 10:12 pm

Postby SkipSanders » Tue Feb 27, 2007 6:47 pm

The 2050 should work correctly, if properly programmed to treat the system as a type II system. Perhaps you've been fooling with the fleet map, and changed it to hybrid I/II, which would cause this sort of thing?

N6ATF
Posts: 373
Joined: Sun May 15, 2005 1:36 pm

Postby N6ATF » Tue Feb 27, 2007 8:04 pm

Just went with the steps starting on page 26 - which would default to Type II. Never read the part about type I or hybrid until a few minutes ago, and punched enough buttons to screw up the trunking bank into Error mode.


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