Common DMR Radio Terminology


Technology Enthusiast
Common DMR Radio Terminology

DMR is a digital mode many new ham radio operators are experimenting with. It has been around for some time but some of the key concepts of the mode comes with loads of confusion. Gone are the days where you can just simply tune to a radio frequency, choose a mode like AM of FM and be ready to rock.
  • Code Plugs
  • Talk Groups
  • Color Codes
  • Zones
  • Time Slots
Even some of the most veteran of radio operators have trouble understanding the concepts behind these terms. Only three of them are critical for operation. Can you guess which ones?

In my experience, it actually takes getting your hands a little dirty in the setup before understanding how all of these things come together. One error, and it will fail to work properly.

Not trying to scare you off or make you throw your arms in the air or anything, just trying to stress that attention to details is critical here. After the initial setup, it is much like a channel where you can just set it, and forget it.

So let us go through these terms and try to define what they are and what they mean.

A Code Plug is nothing more than a fancy name for a list of channels and those channel's specific configurations.

Much like an analog radio, to program a channel in, you must know what frequency and mode it uses. A code plug, in its simplest terms, is basically a list of channels and how the radio needs to be configured to get to them. These configurations may include:
  • channel name
  • power tx lvl
  • time out time
  • Frequencies (both input and output)
  • Color code (acts like CTCSS or a sub-audible tone to break a squelch)
  • Talk Group number (like an address for a group of people interacting with same repeater)
  • Time slot (usually either just "1" or "2")
  • zone (not always needed but some radios support and therefore need it)
That is a lot more information needed than a simple analog channel!

Don't get discouraged, once you understand what each element is, you'll understand the need for each of them.

Lets skip channel name. Believe it or not, that is probably going to be the same as Talk Group name. Frequency is also kind of a no brainer. Every channel needs to know what frequency to monitor no matter the mode.

The digital Color Code (CC) has nothing to do with a color. Compare it to a CTCSS or DCS code. Its function is to prevent interference between two repeaters with overlapping coverage on similar frequencies. The proper CC is required for access and is assigned by the repeater's owner.

A talk group ID is a number assigned to a group of people interacting with the same channel. DMR ID numbers are assigned to operators and groups of operators. For example, my DMR ID is 3123906. The group NEARC (North East Amateur Radio Club in Connecticut) has a DMR Talk Group ID of 31257.

These number don't change but can have various numbers on different DMR networks. You likely will not be switching from network to network just yet so don't worry about that. The numbers I gave above are for the network I participate in which is the Brandmeister network.

It isn''t often that you'll be network hopping unless you get totally into DMR and become an crazy expert enthusiast. You wouldn't be reading this if that was you.

Ever wonder how the APRS network exists with so many radios seemingly transmitting and receiving constantly on the same frequency?

It is more obvious there that they share the frequency by collaborating with each other a time for broadcasting and a time for receiving.

We do too in voice but machines are able to do it much more quickly. So quickly that two people can be talking simultaneously on the same frequency digitally without interfering with each other. It is called Time Division Multiple Access.

Most DMR repeaters allocate a time slot to a purpose. For example, time slot "1" may be for folks communicating locally and time slot "2" is for folks interacting with talk groups that need to use the internet for propagation.

Zone are nothing more than a collection of channels. For example, I have a zone for talking with certain talk groups over repeaters in my area. And then another zone for talking with those same talk groups but through a wifi hotspot.

I really wished another name was coined for this.

To most non DMR operators, a hotspot is wifi access point.

A digital mode like DMR use little devices called hotspots like a personal repeater. They behave like little digital repeaters you connect to remote talk groups or DMR IDs with. This might be worth writing about again because it is a very hot topic in the digital communications world.

For now, I'm just going to hope this helped you have a better understanding of what some of these terms are used for in the world of DMR.

I hope to write again soon, so stay tuned.