status bits

[troymail]

When I see a base talkgroup ID like "16" on my location trunked system that is using a "standard" patch configuration for the system, it comes up as "23". This usually means that they have patched talkgroups "16" and "48" together -- I believe this means the base TG for the patch is "16".

Recently the patch is coming up "83" -- is there anything I can derive from this different configuration given it's now "83" vs. "23"?

 

[GTR8000]

Base TGID's are always evenly divisible by 16, otherwise it's a status bit. TGID 23 is really base TGID 16 + 7, which is Multi-Select, i.e. the dispatcher is transmitting on both TG's simultaneously, however the TG's are not actually patched. You have no way of knowing what TG's are multi-selected by looking at the TGID/status bit itself (aside from the one you're seeing the status bits on, 16 in this case), only from listening to the system would you know.

TGID 83 is really base TGID 80 + 3, which is a talkgroup patch. Again, there's no way of knowing what two TG's are being patched together just by looking at the TGID (aside from the one you're seeing the status bits on, 80 in this case), you'd have to listen to the system to figure that out.

 

[GTR8000]

Okay taking a look at Anne Arundel's Type II system, this is what you're probably seeing:

When you see TGID 23, that means the dispatcher is transmitting on FD Dispatch (16) and another TG at the same time, but they are not patched together. The users in the field can hear the dispatcher on either TG, but can't hear each other. Based on your observations, it appears that they are transmitting on FD Dispatch (16) and FD Tac 1 (48) simultaneously. But again, you have no way of knowing that just by looking at TGID 23, you had to listen to the system to figure that out.

When you see TGID 83, that means FD Tac 2 (80) is being patched to another TG. Since you didn't mention what other TG was active at the same time, it could literally be any other TG on the system. You'd have to wait until TGID 83 pops up again, then quickly scan to find out what other TG is active and showing a +3 status bit.

 

[troymail]

Thanks guys -- the bottom line is the status bits tell you there is multi-select active but you can't tell just based on that which talkgroups are involved.

The "23" is fairly normal (in fact +7 is common for many talkgroups on the AA System). I have these all programmed to catch unusual/priority messages (I keep many "routine" talkgroups locked out). However, for some reason, they used "83" all day one day last week - and I'm trying to figure out what was up with that.