DMR vs C4FM vs D-STAR: the differences, and how to choose
By IU4VRB — Licensed Italian radio amateur and the developer of HamQRG. Updated October 5, 2026.
Amateur radio arrived at digital voice three times over, from three directions, and the results do not talk to each other. A DMR radio cannot work a D-STAR repeater. Choosing between them is mostly a question of what is already on the air where you live.
DMR
Borrowed from commercial land mobile radio, which is why the equipment is comparatively cheap. DMR splits each channel into two time slots, so one repeater carries two conversations at once. Access is organised around talkgroups — numbered rooms you join — and a colour code, which does the same job as a CTCSS tone in keeping other systems out.
Programming a DMR radio means building a codeplug, which is genuinely more work than tuning an analogue set. In return it is the most widely deployed digital mode worldwide, largely through the BrandMeister network.
C4FM
Yaesu's System Fusion, developed for amateur use rather than adapted to it, and the easiest of the three to live with. A Fusion repeater accepts analogue FM as well as digital and switches automatically, so nobody is locked out. Rooms are reached through Wires-X, and a DG-ID number can restrict access in the way a colour code does on DMR.
D-STAR
The oldest of the three, developed with the Japanese national society and long associated with Icom. It carries a callsign in every transmission, routes by callsign rather than by room, and has a low-rate data channel alongside the voice. Its footprint is smaller than it was, but it remains strong in parts of Europe and Japan.
Choosing
| DMR | C4FM | D-STAR | |
|---|---|---|---|
| Origin | Commercial | Amateur (Yaesu) | Amateur (JARL / Icom) |
| Analogue fallback | No | Yes, automatic | No |
| Access parameter | Colour code | DG-ID | Callsign |
| Voice codec | AMBE+2 | AMBE+2 | AMBE |
| Channel | 12.5 kHz, two time slots | 12.5 kHz | 6.25 kHz |
| Main networks | BrandMeister, TGIF | Wires-X, YSF reflectors | REF, XLX and DCS reflectors |
| Setup effort | High (codeplug) | Low | Medium |
C4FM vs D-STAR
The two modes designed by and for radio amateurs. Both carry your callsign in the signal and both have a data channel alongside the voice. The practical differences are elsewhere: a C4FM repeater lets analogue FM users in, a D-STAR repeater does not; C4FM radios come from Yaesu, D-STAR radios mostly from Icom, with a few from Kenwood. D-STAR routes calls by callsign, which is powerful and takes some learning; C4FM rooms are picked from a list.
D-STAR vs DMR
DMR radios are cheaper and made by many manufacturers, because the standard comes from commercial radio. DMR also fits two conversations on one repeater. D-STAR asks less of you on day one — no codeplug, your callsign is your identity — and uses a narrower channel. In most of the world there are many more DMR repeaters than D-STAR ones, which usually settles it.
DMR vs C4FM
Both use the same AMBE+2 voice codec, so they sound similar. DMR wins on radio price, network size and repeater count; C4FM wins on ease of use and on not shutting out analogue users, which is why some clubs prefer it for a shared repeater. If your local repeater is a Fusion machine, a C4FM radio also works it in plain FM.
Can one radio do all three?
A few radios handle more than one mode, but most are built for one. The cheap way to try a mode is a hotspot: a small MMDVM board that connects to the internet and talks to your radio over a few milliwatts, and that speaks DMR, C4FM and D-STAR alike. It does not need a repeater in range.
The honest advice is to ignore the specifications and look at what is on the air within reach of your antenna. A mode with no local repeater is a mode you will not use, however good it is.