Hi. I have a device that ouputs .dvr files for audio recording. Its like a dictation machine.
I got it in china.
Unfortunately I have no I Idea what kind of codec it is and how to convert or play it.

Anybody know what this could be?

I have no idea too, but if you need software for transferring to PC and converting, I can send it to you.

Usually with your dictation machine comes a cd including softwares to convert these files do wav or other formats. I have an old crappy voice recorder machine too that uploaded to *.s2400 format in my pc. You may just search for your dictation machine model on internet and download drivers or software for it.