UID Numbering sequence questions.

[gcopter1]

I regularly listen to two trunked P25 Systems.

I'm compiling UID's for one of them.

The system in question, uses a mutual aid TG so, different agencies use it.

To distinguish one agency from the other, I listen to their initial broadcast (when they Identify the agency name) I then take a note of their UID and add it, to my scanner.

I notice that, for any given agency, there's no single UID used.

Oftentimes, I can ID them, as they might use a UID already compiled for them, at others, it is a new number.

But every now and then, a new UID pops up whose number is sequential.

For example, Dispatch for agency "A", might have UID's in a series, like; 1050012, 1050013, 1050015, and then a new one, 1050016, pops up.

My questions are, what's the logic behind this?

Why would the system do this?

In my mind, I equal a UID, as a number given to a particular physical radio.

If so, I'm perplexed as to why this number changes when it comes down to dispatch radios.

 

[Mr_Boh]

Do you know if they are using ISSI and/or CSSI?

As the patching happens TGs and UIDs are assigned based on a range, and would depend a lot on configuration.

 

[gcopter1]

Do you know if they are using ISSI and/or CSSI?

As the patching happens TGs and UIDs are assigned based on a range, and would depend a lot on configuration.

No, I don't.
But, from your answer, at least I now know, UID's aren't treated as a number assigned to a particular radio.

Thanks.

 

[Mr_Boh]

Typically, they are on the home system. Would depend on how they are managing mutual aid - unless of course they are doing something unusual.

Again - as you mentioned, the "typical" way is one ID per one physical subscriber (radio)

 

[talviar]

If its trunked--- unless some one intentionally (not a system programmer) or accidentally (system programmer) duplicated an ID,,, one radio, one ID. Sometimes a radio may have multiple ID's for the same system for ID purposes when the radio keys up.

to answer your other question- It's up to the entity programming the radios to determine how they assign ID's... On my portion of the ICORRS system, I assign for Fire and EMS numbers in groups of 25. Police get sequentially assigned. out of a pool of numbers issued to police.

 

[Mr_Boh]

Unless you have ISSI or CSSI or use some sort of app or cloud based PTT that uses the subsystem interface. Then the foreign system subscribers and TGs are dynamically assigned.

 

[hill]

Here in Maryland the ids for each radio follow a system set up, so each county has a range of ids assigned to it so no issues with others using the same ids. It the same with state agencies they all have a range of ids to use on their radios on our statewide system. As many counties access the state system for large scale events and a lot of mutual aid between the counties it works very well.

The first three digits of the id are assigned to each county.

So one county fire ids may be something like 2241234 and the other next county would be 24698765

 

[Mr_Boh]

Yup. Works well - this also extends beyond MD btw... should be able to have good interoperability in quite a large area with little ID overlap. Also makes programming really easy when your ID is the same on multiple P25 systems... now we patiently await the last of the Type II to P25 upgrades...