MMDVM Modems for MTR2000 & MASTR III

MTR2000 Version

KS-DMR and WA0EDA are not affiliated with Repeater Builder and do not support Repeater Builder products.

Purchasing a Modem

Modems are no longer available for purchase to the general public. Existing customers may continue to purchase new modems. The articles and files here will remain to support existing customers and DIY builders.

Contact Cort Buffington, N0MJS at for more information

STM32-DVM-MTR2K Version 1 (refurbished – 1 left!): $100.00
Refurbished (formerly used by KS-DMR) Version 1 PCB (does not include Aux I/O card features). All hardware and software updates applied. Comes with a custom designed ethernet extension to relocate the ethernet jack to the rear of the station. USPS Priority Mail shipping (US only) included.

Manuals, Articles & Tutorials


Much of the circuitry of the STM32-DVM-MTR2K and SMT32-DVM-MASTR3 is the same. Both use the same filters, the same modem processors, NanoPI NEO single board computer, etc. Most of the information contained here is applicable to both.


Articles & Tutorials:

Schematics and PCB Layouts



Firmware Updates

Binary Modem Firmware Files For Both Boards.
(Instructions for updating are in the manual).

Compiled on July 27, 2020. Includes support for DMR, D-Star, YSF, P25, NXDN, POCSAG, FM. This version expects the function of the COS input (COS or Inhibit) to be set in the MMDVM.ini file for MMDVMHost. It is NOT compatible with PiStar builds for the NanoPi NEO as of August 2020.

Compiled on December 5, 2019. Includes support for DMR, D-Star, YSF, P25, NXDN, POCSAG. These versions ARE compatible with the PiStar builds for the NanoPi NEO as of August 2020.

Binary Firmware Files for the STM32-DVM-MTR2K I/O Processor
(Instructions for updating are in the manual)

  • ATMEGA328P – 20200404 release with startup light show


The artwork is licensed under the Creative Commons BY-NC-SA 4.0 share-alike license. Which means you may do anything non-commercially you like with it, but you must provide attribution, even if you modify it. Which means you can pretty much do whatever you like, but you have to give credit to the Regents of the K0USY Group, and we prefer you just use the EDA logo.

Older Versions and File Archives