Just saw this in an antique store, recently came out of a diseased mans shed and was just wondering if anyone knows what is or if anybody has any background info on it or something, cheers.
I can not see the two middle photos but it looks like a german PA power amp from the 70ties or early 80ties. There is a switchable high pass filter for "druckkammer" (pressure chamber = horn) loudspeakers...
There is an additional mixer with input selection and EQ in your power amp. You can even connect 600 ohm telephone lines to it. That frontplate looks pretty military to me. This is the perfect device to communicate directly the attack order via telephone to the troops on the battlefield.
There is a telephone in/out, too. (see photo). This device is build for battery PSU. Its an all in one audio device you will find in mobil military communication centers ("Funkzentrale"). The two languages on the frontplate were important for multi-national NATO maneuver.