The chart above can be used as a guide to general DMR code plugs used within the amateur radio community. Commercial DMR usage will be somewhat different in the sense that DMR ID, talk group info, and some other details may be different than what is used in the amateur radio community. We have listed the terms used within this chart with their definitions. Although there are several DMR networks available out there to use, we will be using Brandmeister as an example in this article.
Code Plug: The “code plug” as many users refer to, is a set of instructions programmed into the radio. This is normally done via a connection to a computer using the appropriate cable and CPS. However, many radios allow front panel programming, so the setting can be adjusted without a PC. The “code plug” will contain the operating aspects of the radio such as the user’s DMR ID, radio and button functions, contact list and other related details.
DMR ID: A unique 7 digit ID that identifies each user on the DMR network. This ID is usually issued by radioid.net and can be used in multiple radios as long as each radio is used by that user only. It is advised that the user only have one radio powered up at a time as there may be conflicts when a private call or SMS is received by that user. The ID is not considered an acceptable form of ID by the FCC, so call sign identification is still necessary during QSOs.
Contact List: The contact list is a database of users and talk groups stored within the radio. The user database can be obtained via several sources including radioid.net and via the N0GSG Contact Manager. The user databases do not normally contain talk group (TG) information though. Talk group detains can be obtained via the DMR network you intend to use, such as Brandmeister, or via local ham radio groups. Not all talk groups may be published on the network’s page. Some localities will use the DMR ID of the local repeater as a talk group
Zone: A Zone is a group or bank of channels in the radio. Zones can be setup many ways. Each zone could have a set of channels for specific geographical areas that the user may be in, or by specific repeaters or hot spots that the user may use.
Channel: The channel will contain operating details such as TX & RX frequencies, color code, time slot, and talk group. Channels may be named by however the user sees fit, but the number of characters used on each channel name may be limited depending on which radio is being used
TX & RX Frequency: These are the frequencies uses in order to connect to a repeater or hot spot. Most hot spots are simplex, therefore the TX & RX will be the same. In a repeater setup, the TX will be the frequency that the radio uses to talk into the repeater. The RX will be the frequency that the radio listens to the repeater on.
Color Code: The Color Code is somewhat analogous in the DMR world to the PL tone in the analog world. There are 16 Color Codes (0-15) available for use. The color code programmed on the channel must match the color code that is in use on the repeater or hot spot.
Time Slot: There are 3 tiers in the DMR standard. This has been touched on briefly in a previous article. Tier 2 and Tier 3 are most commonly used in commercial and amateur sectors. Tier 2 incorporates 2 slot TDMA, effectively creating 2 virtual repeaters from one frequency pair. Time slot 1 and 2 can be used independently of each other, allowing 2 separate conversations without any interference with each other. Most hot spots are single slot, and normally slot 2 is used when programming any channels for that hot spot. Repeaters normally utilize both slots and depending on the repeater owner, may have one slot set aside for local use, and another set aside for regional or national use via dynamic linking. Be sure to check with the local repeater sysops or check the Brandmeister or respective DMR network page for details on what time slot are in use and for what purpose.
Talk Group: A talk group, in the commercial sense, is an assigned group of users . In the amateur world, we use talk groups to differentiate between different locations, regions, states, countries, interests, etc. There are currently over 1500 talk groups assigned on the Brandmeister network. These talk groups will each have their own unique number that may be 2 to 5 digits long. Some area may also use their repeater ID as a talk group as well for local radio traffic. For example, the DMR ID for the W4LET repeater in Memphis, TN is 314706. This is also the talk group number used in that area. Most talk groups are available throughout the whole network. This means that you could key up and talk on a German talk group from a repeater located in Tupelo, MS. However some talk groups are only used locally and do not propagate onto the network. Talk group 9 is an example of this. If used on a repeater,the conversation will only stay on the repeater and will not go out over the network. Talk group 2 can be used in a repeater “cluster” meaning several repeaters in an area could be on a cluster and the same conversations be heard on all of them. The cluster has to be setup via Brandmeister first between those repeaters. An easier way to do this is to settle on one of the repeaters DMR ID and use that as a talk group.
Links of interests:
The Brandmeister Home Page
A listing of Brandmeister Talk Groups
Northeast MS Repeaters on Brandmeister:
Northeast MS Talkgroup 31285 Last Heard page
Other nearby regional DMR repeaters:
Coverage of the repeaters listed extend into north MS.
AB5OR Pickwick, TN
KA4BNI Jackson, TN
N4GLE Sheffield, AL
W4LET Memphis, TN