What are contacts in DMR?
The two types of contacts I will cover in this article are group calls and private calls.
The term call in this context stems from the concept in DMR that when you press your PTT button, you are making a call. When you make a call in DMR, you can call a group of users (talk group) or make a private call to an individual user. In amateur radio, we typically make and receive group calls, but it is still useful to have private call contacts in your radio.
A group call contact is simply a talk group. When you create a channel, you will set the default transmit contact. That is, the contact that will be called when you set your radio on a channel and press PTT. As an example, let’s assume your local repeater provides the “Worldwide” talk group with a talk group ID of 1. In that case, you would create a new group call contact with an ID of 1 and a name of “Worldwide.” After that, you can place that talk group into an RX Group List. Many radios do not require this, but some do, you’ll have to check with your specific radio. After that, you can create a channel for that talk group with the RX Group List you just created and have Worldwide as the default TX contact.
A private call contact is the radio ID of another user. On ham radio DMR repeaters, we typically do not make private calls to other users. However, entering private call contacts into your radio allows the radio to display an alias for the user you are currently listening to rather than their radio ID. My preference is to simply use call signs. For example, if you enter a private call contact of 3139024, you could set the name to my call sign, KD8TWG. Then, when you hear me on the radio, my call sign will display on your screen. Private call contacts are entirely optional and are simply used for the convenience of showing other users’ names or callsigns.
Other types of contacts exist, but they are out of the scope of this article.
Questions, comments, concerns? Let me know in the comments!