One other comment. The Becker and Dittel boxes seem externally identical but are not interchangeable. The only reason I know this is because I tried once to plug a Dittel hand microphone into a Becker box.
While the 5-pin DIN plugs on the side are wired the same (pin numbering is the same for mic, headphone, PTT) the pin spacing is different. The Becker's pins have a 45 degree spacing while the Dittel's pins have a 60 degree spacing. I believe the Becker's are DIN 41524 while the Dittel's are DIN 45322. See
https://en.wikipedia.org/wiki/DIN_connector.
Oh, the minutia that I get myself into sometimes. Must be OCD*!
Thanks, John.
* Actually, it should be CDO. Then it is alphabetical and all is right with the world.