DMR Operation & Functionality

Background

Users may remember or have used “DMR Direct Mode”. This means, that the user could select a single DMR Master server from a drop-down in the main Configuration Page, and that was added directly to an MMDVMHost connection. Ergo, that is the one-and-only DMR connection that would work on a hotspot.

At some point in 2021, I moved WPSD away from the legacy DMR Direct mode paradigm, and there is no more “Single Master” DMR selection any longer. Instead, the user is presented with myriad “out-of-the-box” DMR Network selections, each with their own selectable servers (“masters”).

This is because DMRGateway is now the default DMR connection mechanism, and this is where we’ve seen some user confusion.

What is DMRGateway, MMDVMHost, and DMR Gateway Mode?

I feel the need to explain this, because I see both a lot of misunderstanding, as well as misinformation being conveyed by self-proclaimed experts/Dunning-Kruger-affected in the various online communities…

  1. DMRGateway is software that connects to various DMR networks. It can support connecting to 6 networks simultaneously (vs. MMDVMhost’s single master/“Direct Mode”). DMRGateway also provides powerful and flexible rule-set creation (complicated for “appliance operators”, and largely misunderstood by many self-proclaimed “experts”) to help users route DMR traffic to their desires/requirements[1]. DMRGateway then routes the DMR network traffic to MMDVMHost…

  2. MMDVMHost is the host software that “talks” to the MMDVM modem itself.

  3. DMR Gateway Mode instructs MMDVMHost to use DMRGateway for the routing of DMR traffic, rather than MMDVMHost itself.

MMDVMHost has been moving away from any “Direct” connections (to any mode, as a matter of fact…not just DMR), in favor of mode “Gateways” (e.g. YSFGateway, P25Gateway, etc.). In light of this, WPSD has followed suit, and its Configuration Page does not provide means for a Direct DMR connection/single master any longer. And as mentioned above, this WPSD design decision was deliberate.

Depictions of flow and operation

Here is an example ASCII diagram of the (legacy) DMR Direct (single master) Mode flow & operation:

Rig <--> Modem <--> MMDVMhost <--> DMR Master Server (e.g. BrandMeister)

Here is an example ASCII diagram of MMDVMHost in Gateway Mode flow & operation, using DMRGateway with multiple example networks:

Rig <--> Modem <--> MMDVMHost <--> DMRGateway as Master \
							 | <--> BrandMeister
							 | <--> XLX
							 | <--> DMR+
							 | <--> TGIF

WPSD DMR network “mappings”

DMRGateway can support connecting up to 7 networks, even simultaneously. These networks are defined in DMRGateway’s configuration file as:

  • DMR Network 1-6

  • XLX Network

When using WPSD’s Configuration Page to enable DMR networks in DMRGateway, here are the pertinent mappings it configures in DMRGateway:

  1. DMR Network 1: BrandMeister

  2. DMR Network 2: DMR+ / FreeDMR / HB-Link and User-Added Custom Hosts

  3. DMR Network 3: DMR2YSF / DMR2NXDN Cross-Over Modes

  4. DMR Network 4: TGIF Network

  5. DMR Network 5: SystemX Network

  6. XLX Network: XLX Master, chosen by the user

  7. Custom DMR Network, defined by the user

Talkgroup prefixes

Out-of-the box, when configuring one or multiple DMR networks in DMRGateway mode, some (most) networks require the use of talkgroup “prefixes” (and 0-padding digits) in order to use those talkgroups. This is for two main reasons:

  1. There are inevitable talkgroup number overlaps and collisions between the various and disparate DMR networks. Prefixes are the only reliable way to route DMR talkgroup traffic when connecting to multiple/simultaneous DMR networks.

  2. Prefixes allow for talkgroup name lookup functionality

These prefixed talkgroups are programmed into your DMR radio in place of the standard talkgroups that you would use if you were using a repeater and are only used when you communicate via your hotspot on that network.

Talkgroup prefix mappings

When in the main Configuration Page, you’ll see notes in the various DMR networks, such as, “Uses “4/5/7/8” talkgroup prefix”, etc.

Here are the prefixes for the networks available in the Configuration Page when they are not set as the primary network:

  1. BrandMeister: Prefix “2”.

  2. DMR+ / FreeDMR / HB-Link / Custom Hosts: Prefix “8”.

  3. DMR2YSF / DMR2NXDN Cross-Over Modes: Prefix “7”.

  4. TGIF Network: Prefix “5”.

  5. SystemX Network: Prefix “4”.

  6. XLX Network: TG 6, and Prefix “6” to change XLX modules.

  7. Custom DMR Network, Prefix “9” when “Automatic Rewrite Rules” is selected.

One network can be selected as the Primary network by selecting it from the dropdown alongside the checkbox that enables DMR on the configuration page. The default primary network is “Brandmeister”.

When selected as the Primary network, that network will not have the prefix listed above applied.

As an example, We select Brandmeister as the primary network. TG 91 will simply be for BrandMeister World-Wide; no prefix used for BM. TG 8000321 would connect you to TechChat TG 321 on DMR+_QuadNet and TG 4002350 would connect you to UK ChatterBOX TG 2350 on SystemX. Note the 0-padding after the prefix and before the actual network’s talkgroup numbers.

Another example, we select DMR+ as the primary network and enable both Brandmeister and DMR+ IPSC2-VKHOTSPOT. To talk on BM TG 91 you will need to program it as TG 2000091 in your radio’s codeplug. To talk on VKDMR TG 505, Australian Call TG, you just program it as TG 505.

Selecting a primary network that is connected to the same network as your local repeaters means you won’t have to have separate, extra, digital contacts in your codeplug to access the same network no matter whether you access it via your hotspot, or via your local repeater.

Tip

As a general rule, most networks that require prefixes; the talkgroup numbers will need be 7 total digits.

More lovely ASCII depictions:

TG 321 on DMR+_QuadNet: Prefix "8" + "000" + "321" = TG "8000321" (in the dashboard and in the rig/codeplug)

Custom edits to the DMRGateway config file

Once enabling and configuring DMR networks in the Configuration Page, it allows DMR and DMRGateway to operate in somewhat of a basic setup; with settings and options determined by me and a bunch of user and developer feedback. I call these “stock config settings”.

Since these settings/options may not work for every user, users can edit the DMRGateway config file by hand or in the DMRGateway expert editors in the Admin section.

However:

Any subsequent changes using the main Configuration Page will blow away/remove any custom changes you have made to your DMRGateway config file, and replace them with the “stock config settings”[2].

If you happen to apply changes using the Configuration Page after custom DMRGateway config edits and become victim to your edits being changed, you can always restore your DMRGateway (and the rest of your configs) by leveraging the WPSD Profile Manager.

You are not locked into any particular DMR network or DMR settings!

It is important to note, that you are not locked into the available DMR Networks or DMR settings in WPSD. You must remember, my software is simply a pretty front-end / dashboard / configuration tool for the software that actually connects your rig to the various networks.

You are always able to hand-edit your DMRGateway and MMDVMHost config files to do/connect/use whatever DMR network you want with your own settings / preferences.

User-Added Custom DMR Hosts Operation

Users can add custom DMR Hosts/Masters using the DMR Hostfile Editor in the Advanced section.

Once a user adds a custom host, it will be available for selection/use in the configuration page, under the “DMR+ / FreeDMR / HB-Link / Custom Hosts” section.

Custom hosts are typically toward the bottom of the Master selection drop-down.