That's a good question and I don't know the answer. If you compare the two systems there is no visuable difference beside the design.

I've searched the web for informations and found some bits about the systems:

faq by Dale Hansen

old-computers

But both have no infos about your question.

Anyway, the interesting thing is that according to Dale Hansen the system was released in 1976? Two years before the Interton VC-4000 and also before the Atari VCS? I have no idea on what informations this is basing. The oldest copyright notes I've found so far for this systems are 1979.

I did have a quick look at my video-game related litrature and found articles about this systems only for the years 1981-1983 + a catalog which is also from 1979 and contains the first 14 games as released. (The ones which were available in “old” Radofin style boxes.)

Another mystery.

Dieter said:

Have 1292 and 1392 been released at the same time or have the 1392s been released some years after the 1292s?

The “Expand your entertainment horizons!” catalog lists both models from Radofin. The catalog is from 1979. If the system is also from 1979 (and not from 1976) they would have started it with both version… (or would at least have had plans for the 1392-model)

maybe these joysticks did not break that easy than for the 1292 ;-) i have seen more 1392 systems with intact joysticks...

but changing a complete system for just these breakable joysticks would be nonsense.

i think it was a question of style. the 1392 looked a bit more modern than the 1292. maybe the companies that sold these systems demanded a more "stylish" design.

also every system seems to exist in 2 colors a grey or black 1292 and a black and alsmost white 1392.

haha one year before the first pongs were produced by interton in germany - never!

that´s also one year earlier before atari brought out their first home pongs (atari c-100)

Dieter said:

Quote from Dale Hansen's FAQ:

This group of consoles is believed to have started with the Interton VC-4000 (produced as early as 1974,but sold in 1978)

I can hardly believe that the VC-4000 has already been produced in 1974???

Somehow I have the feeling that all his dates are 3 - 4 years too low

Don't know when they started to develop it, but it was presented to the public 1977 at the IFA in Berlin and in the shops in 1978.

And yes, the dates are a bit strange. Interton was in the videogame business since 1974 so maybe he mixed something up?