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DMR Administration

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What is DMR?

Please read the document here. All admins should have a basic understanding of DMR, how it works, and how it is set up.

DMR is particularly challenging for Hams as it is digital technology playing in an analog world. Hams are used to just dialing in a frequency, tone, and offset and being able to get on a repeater. This is not how DMR works. DMR was designed for the commercial and government world, and with the next generation of DMR hitting the market, the older generation equipment is flooding the secondary market and being snapped up by Hams. It used to be cost-prohibitive to purchase DMR radios, but there are plenty of discount radios being brought to market now. DMR requires a “code plug”, which is essentially a memory of the radio's settings, modes, channels, and other parameters needed to access the repeater. These code plugs can be a challenge to create as the learning curve is steep.

There is a lot of peer pressure within the Ham community for new Hams coming into DMR to learn how to create their own code plugs. To create one, the Ham needs to know the repeater's input and output frequencies, the color code (like PL tone), and the available talk groups. The talk groups each have an ID code and the correct ID code must be entered in to access that talk group. DMR is also divided into two time slots. Two time slots can be used at the same time. talk groups are usually assigned to one talk group or the other, so knowing which time slot a talk group is on is important. The final parameter is how the talk group is activated. It can be on full-time, only come up when someone activates it by bringing up that talk group on their radio and keying up, or during a scheduled time.

Most DMR repeaters are Internet-connected back to a c-bridge. A c-bridge dynamically connects all repeaters together that are using the same talk group at the same time through that c-bridge. It just gets more complicated from there as c-bridges can also be interconnected.

Repeaterbook attempts to gather the information needed for Hams to create their own code plugs.


On, we use certain nomenclature that matches the DMR community to reduce the probability of confusion. it is important to know these terms and what they mean.

Wide Network

This is the flavor of the DMR system. There are three different flavors, DMR-MARC, DMRplus (DMR+), DCI, and BrandMeister. The architecture of each is a little bit different. We track the Wide Network because it influences the architecture of a client-radio codeplug.

Local Network

A local network is a group of repeaters that have very similar talk groups. They tend to be linked to each other through the talk groups in various ways and connect to the same c-bridge.


This is like a server. The Local Networks connect to the c-bridge which handles the routing of talk groups. The c-bridge can route talk groups to other repeaters within the same local network or send it out to other c-bridges or even cross over to other Wide Networks.

Editing a Repeater's Assigned Talk Groups

First of all, you need to understand what a talk group is and why DMR repeaters use them. Talk groups are not just used on DMR repeaters, but also exist on P-25 and other repeater digital modes. Essentially, a talk group is a channel within a channel. The talk groups are assigned a numerical code and when all of the other radios are “tuned” or listening for that particular talk group code, or ID, when someone talks they all listen. A radio tuned to the same repeater frequency and not listening for that talk group ID may not hear anything (the only time you would hear something is if you had your radio set to listed to all conversations, regardless of the talk group.).

Since DMR repeaters are typically linked to centralized computer hubs, called c-bridges, using talk groups allows repeaters without a user actually monitoring a talk group to remain quiet. An exception is if a repeater has programmed that talk group to be full-time or only activated by PTT.

So, another caveat to the talk groups is the full-time vs. PTT monitoring. Repeaters have the option of monitoring and repeating all traffic for a talk group all the time. Usually, owners will program a talk group to only be monitored when a user requests it. This can really cut down on the chatter and is a common setting for very large area talk groups, like the Worldwide talk group. For a user to use that channel, they bring up that talk group on their radio and key the radio. This will send a message to the repeater to begin actively monitoring that talk group. This is the same in concept to dialing up an AllStar room, IRLP node, EchoLink node, etc. The repeaters are also set up with a hold off timer which is how long the repeater will listed to that talk group without hearing a local key up. Repeaterbook does not track hold off timers.

The final caveat to a talk group is the time slot the talk group is on. DMR repeaters can actually handle two conversations at once, one on time slot one and one on time slot two. This concept would seem impossible for users of analog repeaters because doubling would occur. However, DMR repeaters can “hear” two radios at once on two different time slots. Essentially, the packets a radio sends when keyed up identify if the radio is on time slot one and time slot two, The repeater then accepts these packets, stitches them together, and sends them on to the correct time slot and talk group. DMR repeaters actually don't allow doubling and can reject a transmission from a radio when the time slot is already in use.

So, to add a talk group to a repeater, you need, at minimum, the time slot and the talk group. You can enter the talk group info without the access (full-time vs. PTT), but users appreciate this information. With this data, you can edit a repeater from the “manage talk group” link.

From the new window that appears, you have three options. One is to Add a Network, Add a Single Talk group, or Bulk Add. You should add the Network (c-bridge) if you know what it is.


Networks are preferred as they entered into the database with all of the talk groups and time slots for that repeater's affiliated network. If you add the correct network, the repeater's details page will automatically retrieve all of the task groups for that network. It saves a lot of time because you don't have to enter in all of the individual talk groups. It also allows admins to make a single change for the network instead of edit each repeater one by one.

To manage networks, please see DMR Network Administration below. This module will allow you to create and edit a DMR network.

Custom Talk Groups

Occasionally, a repeater may have a different talk group access configuration (i.e., PTT-Activated, Full-Time, or Scheduled). You can override this setting by adding the talk group as a custom talk group. You can only do this if the access is different. For all other issues, please read about DMR Network Administration.

You can also add a custom talk group if the talk group is not a part of the network, for stand-alone repeaters, or where the network info is not known.

Bulk Add

Bulk add is a spin off of the Custom Talk Group method of adding. With this method, you can select a preconfigured set of talk groups from a c-bridge or network. A list of all the talk groups available to that network will appear. Sometimes, not all of the talk groups are available for a repeater, so you simply select the ones that are. You can also change the time slot and access configurations on a talk group by talk groups basis. The talk groups are then added to the database just like the single talk groups are added. Maintenance is performed from the single talk group module.

DMR Network Administration

From the admin dashboard, you can access the DMR Management Module from the link in the Tools section of the menu. It will open a new page. This home page displays all of the current networks. A checkmark is shown if you are subscribed to the network. If you need to create a new network, you can click Create a Network from the menu.

There is a general rule to adding a network. When adding talk groups, only add talk groups that are common to all repeaters on the network. This applies specifically to the talk group number only. Talk groups with different time slots and access methods (i.e., PTT-activated, Full-time, or Scheduled) can be handled by adding custom talk groups.

When you are subscribed to a network, you will receive notifications from the system whenever an admin makes a change to a network.

Managing Network Subscriptions

Click a network from the home page. The network's home page will show your current subscription status. Simply click the subscribe or unsubscribe link from the menu to perform the desired action. Whenever new networks are created, all admins will receive an email notification with a link to the subscription module to allow for subscribing to the DMR network. Whenever a change is made to a DMR Network, an email notification is sent to all subscribed admins. This email also provides a link to unsubscribe from the DMR Network.

Adding a Network

To add a new DMR Network, click the link from the menu on the DMR Management home page. You will be taken to a page where you can name the new Network. A new network with no talk groups will be created. All admins on the site will be immediately notified by email. The email will give the admin the opportunity to subscribe to the new network you have created. As the creating admin, you will be automatically subscribed to the new network. The network will also be immediately available from the repeater edit pages.

Above, is in effect, what is happening, but behind the scenes, a network is not actually created until the first talk group is assigned to it. Once the first talk group is added, the network becomes available for assigning to a repeater. As you add talk groups, any subscribed admins will be notified.

You cannot technically delete or rename a network, but if you delete all of the talk groups, the network will, in effect, also have been deleted. The network will disappear from the database and will no longer be available for selecting or modifying. Deleting talk groups also notifies the subscribed admins.

Adding and Deleting a Talk Group to a Network

Important: Only common talk groups that apply to all of the repeaters that connect to this network should be added. For example, if all the repeaters but one allow access to a specific talk group, do not add the talk group to the network. If a repeater allows access to a talk group that is not available to all of the repeaters on the network, then use the custom talk group function from the repeater edit page to add the single talk group.

Adding and Deleting talk groups is done from a network edit page. There is not an edit function to edit a specific talk group. If there is a problem with a talk group, you must delete it and then add a new one.

To add a talk group, select the talk group from the drop down menu. Then select the time slot and access. Click save and the talk group will be added. Repeat until all the talk groups are added. If you make a mistake, click the trash can to delete the talk group.

Currently, admins cannot make modifications to the talk groups that can be chosen. If you need to change the name of a talk group as it is shown in the drop down menu, please contact the site admin with proof of the correct name.

Talk Group Database

You can view all of the talk groups in the talk group database available for assignment.

These are the talk groups that you can add to a repeater either via a custom talk group or adding to a repeater network.

The talk group name itself is hyperlinked to another page that will show all of the networks that have this talk group assigned and/or the individual repeaters that have the talk group custom assigned.

The network then can be clicked to be taken to the list of all of the repeaters within that network.

Only admins that have a high-proficiency with DMR have access to edit, add, or delete talk groups from the master databases. Requests are made from the Forum so that all admins that have subscribed to the DMR Forum can weigh in on the change.

User Submissions

Currently, there is no talk group module for users to propose talk groups. Users must put the talk group info in the notes section of the repeater request form. In the future, a form will echo out the current talk groups and allow the user to propose changes.

dmr_administration.txt · Last modified: 2021/02/27 14:11 (external edit)