I think tape recorder was connected via the DIN-5 male socket. I'll check it out tomorrow morning and let you know - after all the decades of not loading anything from a tape I totally forgot everything about a tape recorder
Btw, what's meant by your "Floppy drive here is full not standart?" At Didaktik, they developed their custom filesystem, so the disks were rendered incompatible with MS-DOS and FAT-12. There are, however, tools which allow you to transfer files from and to an image or even physical Didaktik disk.
More info tomorrow