DMR 103

Overview

The contact list is a critical part of how your radio works. In Section 102, we discussed the different call types. Each call type had a range of possible ID’s. Some Call Types were based on other Call Types and may share the same ID. Some of the nomenclature below may sound the same and is likely related, but not the same. 

Terminology

Private ID

A private ID is a unique ID number that is "issued," or "assigned" to each radio or individual.  The Private ID range, in decimal, is be between 1 and 16,776,415. The authority to issue or assign an ID belongs to the system owner. In the amateur realm, most have agreed to adhere to RadioID.net for ID assignments. Many systems require a valid ID via radioid.net prior to being able to use said system. Many systems get almost live updates so it's relatively quick  from ID assignment to being able to use a DMR system.

If you are an amateur looking to use DMR you can register for an ID here: https://radioid.net/. If you are a commercial radio user, please find your system administrator or vendor that has deployed or is deploying your system for an ID. PLEASE do not just make one up. This will become clear in the System section.

Group ID

A Group ID like a Private ID is a unique ID, however, in this case are assigned solely by the system owner.  The  Group ID range, in decimal, is be between 1 and 16,776,415. Does this look familiar?  That's because it is, but it's not. I know, I know, your asking what the heck. While the ID's may have the same range, remember that call TYPE is different for GROUP and PRIVATE calls. Now to confuse things just a little more. During Group calls, your Private ID is also sent. Some systems have the ability to filter on Private and Group ID's to determine if the user is authorized, anyway, more on that later. Systems have no best practice implementation plan, so they are all over the place. Here is a gotcha though. Some radios will not allow you to enter the same Call Type ID or Alias more than once in the contact list. If you assign a Group Call ID of 2 and name it “Local,” you may not be able to reuse Group Call ID 2 or the Alias "Local" again, so you may have to put some thought behind programming your radio.

Contact List

The Contact List is a table that correlates a Call Alias, a Call Type, and the Call Identification (ID) number to make a call. I broke this section into parts to try and keep it simple. Again, I am using Group Call and Talkgroup interchangeably, since they refer to the same settings. I am going to list them in order of priority they should be added.

Group Call / Talkgroup ID’s

I start building my contact list with the talkgroup ID’s. This ensures I have enough room in my contact list to capture them all. Talkgroup ID’s can suck. You might ask why I take this tone? Well, talkgroup ID’s may not be the same across c-Bridge’s and the BrandMeister system. The list of talkgroups on BrandMeister are easy, all repeaters connected follow the same talkgroup ID assignment, which can be found here. c-Bridges aren’t as easy. Each c-Bridge can have its own talkgroup ID assignment. If you plan to use your radio in an area that employs a c-Bridge, you’ll need to research what talkgroups are in use on that system.

It is possible that a talkgroup ID can be duplicated between the systems with different intents. Most radios will not allow the duplicate use of a talkgroup ID, nor a duplicate talkgroup/call alias. If you come across a duplicated ID, there isn’t much I can offer to fix that. If there is a duplicated alias, it’s easy to add something that makes it unique. I tend to add “ – C” for c-Bridge or a “ – B” for BrandMeister. As you build your contact list, please add as many as you want. There is a good chance that you will add more than you’ll ever use. You can always update your contact list as your get more comfortable with DMR.

Example: Washington, Group Call, 3153

Other Call Type Contacts

I added this section to address the desire to add ID’s to your contact to support the other call types, like Alert Call. This would be the time to add those. Alert Call ID’s must duplicate the Private Call ID’s of those you wish to Alert Call. Remember that the call type is different, so it will not error on duplication of the ID. It may however error on the duplicate Alias, a good work around is to add “ – A” at the end for Alert Calls.

Example: Brien (K7KSN) -A, Alert Call, 3153169

Example: Phil (KC7SVI) -A, Alert Call, 3116481

Example: Michael (AF6FB) -A, Alert Call, 3106609

Private Call ID’s

Adding Private ID’s is a topic I struggle with. There are a few radios that will accept the entire worldwide ID list. I’m not sure how practical it is to load the whole list into your radio, but the list is growing faster than the radio manufacturers can build support for it. Knowing that the list is so large that it can fill up your entire contact list memory, leads to the order in which we have added the contacts to this point. Using the downloaded list would require you to manually update the list in your radio, reuploading the list regularly to your radio. Since we are still required to ID with our callsigns, verbally, adding private ID’s and their aliases is just a bonus. This will allow your radio to look up a received Private ID and display the alias, usually the name and the callsign of the person speaking.

There are good reasons to add Private IDs to your contact list. I typically add the people I know. This allows me to quickly access them in the address book. There are some neat features that DMR supports, like a private call, or polling of GPS, or sending text messages, and even checking to see if they are online. All of which I can do without the person being in my contact list but having them in the contact list, makes it a lot quicker. Again, I wouldn’t typically do this to everyone, just a select few regulars.

Example: Brien (K7KSN), Private Call, 3153169

Example: Phil (KC7SVI), Private Call, 3116481

Example: Michael (AF6FB), Private Call, 3106609

Note: I didn’t discuss the use of All Call in your contact list on purpose. All Call is typically disabled on both c-Bridge’s and the BrandMeister systems. This isn’t to say you won’t find exceptions for using the All Call Call Type. All Call requires that it be enabled on the radio and by default, it is usually not enabled. There are great reasons to use All Call to support events and alike, however, it can cause confusion if it’s not explained ahead of time.

Summary

Your contact list is the basis for radio operation and programming. Ensuring it is inline will reduce the complexities during programming. I did mention at the beginning that you’d need to do research on the system and the repeaters your going to connect to. From that research you should now at least have a list of Talkgroup ID’s and aliases they use for the system you want to add to your radio. You may have already started building your contact list for your radio, which is great. If not, that’s fine, we will discuss it again under Section 105, Programming.