With this converter, you can connect to a Nixdorf 8870 via Telnet instead of an BA80 or DAP4 VDU. The converter is connected to a V.24 port of the 8870 and supplies two telnet channels (one for the master VDU, another one for the slave VDU) on different TCP ports.
The firmware development is still in progress. You find some pictures and a video in the pictures folder. The 8870 protocol description is here.