Hey Dk,
Well I think there are several ways that patches can be setup. These are just from observations that I have made from watching etrunker...
I have seen patches pop up in e-trunker -
1. Patch defined.
2. Talkgroup 123 added to patch xyz.
3. Talkgroup 234 added to patch xyz.
4. Talkgroup 345 added to patch xyz.
The times on events 1-4 is all within one or two seconds. This tells me that the patch is pre-configured.
The other type of patch that I see is this:
1. Patch defined.
2. Radio xxx affiliates
3. Radio yyy affiliates
4. Talkgroup 123 added to patch xyz
5. Radio zzz affiliates
6. Radio aaa affiliates
7. Talkgroup 234 added to patch xyz.
This type of patch seems to come up gradually, and I believe these are manual patches initated on the dispatch console.
My understanding is that patches can only be started using entire talkgroups. The dispatcher adds talkgroups to the patch and all users who are on those talkgroups are interconnected.
I have also seen some rather interesting patches involving EDACS fleet wide talkgroups. One dispatcher seems to like doing this:
1. Patch defined.
2. Talkgroup 01-000 added to patch xyz.
3. Talkgroup 09-141 added to patch xyz.
4. Talkgroup 09-142 added to patch xyz.
This is a more interesting kind of patch. I think that in this situation:
a) Any user on 09-141 or 09-142 will receive and transmit into the patch.
b) Any user on 01-xxx talkgroups will hear the patch, it will override any local traffic on those talkgroups but they can't transmit back into the patch.
Some more interesting notes..
When using "scan" on an LPE-200, I have observed that you will not received patched audio from talkgroups that you are scanning.
For example, your display is showing TG 08-081, and scan is activated. Your radio is programmed to scan 08-082, 08-083.
If 08-082 is added to a patch, your radio will not lock into this as part of the scan. It will only open up and participate in the patch if you actually put the radio on that talkgroup directly.
If you want to scan patches, you will need to have the actual patch talkgroup ID in your radio (ie. 15-152 or whatever). This works for me, but it would be a pain if your system always uses patches.
Regarding Fleet-wide calls, I have observed fleet wide calls on an LPE-200 - it shows "FLEET" in the display instead of "GR xxxx".
I have encountered a couple of weird EDACS systems that are multi-zone. Instead of carrying a talkgroup on the same ID on each system, they patch them between different zones on different talkgroup ID numbers. For example in zone 1 the talkgroup is 11-081 and in zone 2 the same TG is 12-021. They are tied as a patch, which makes scanning the talkgroups a total pain in the butt if you are using an LPE. (Remember what I just said about scanning across patches).
Digital / analog talkgroups and patches...
I have also seen digital talkgroups patched with analog groups. This has always caused the patch to drop to analog to accomodate the analog users. There may be other options, but I suspect that this is pretty common.
Well that's about it, those are purely my observations. Maybe other systems do it differently. I'm sure there are rules / exceptions that I'm not aware of.
Cheers!
SD.
