As a task, it was the pressure of a RS232 data Anschusses (only TX, DTR and GND are available) clean without printer to load in a Linux software. However, the simplicity of the former COM ports seems to have been lost due to incorrect voltages over the years. A Raspberry Pi can no more like a banana pi do something with the data (3.3V max.), As well as a "cheap RS232 USB Adapter" Amazon completely failed (here 12V should supposedly even go).
The purchased here Cables / Adapters I feel in the 90 back to where a "stty baud rate" along with a "cat / dev / ttyS1> file" was no magic.
Thanks to the consignor for the fast delivery and the manufacturer for this magnificent "new old" piece of art!