Following Process works totally:
Via CUPS webinterface at localhost:631 Add a printer Choose JetDirect Apply socket://the.ip.of.theprinter
Choose PPD file
Save. Issue a testpage.
Now at least restart printer & cups and/or reboot computer.
Eventually cancel testpage and re-issue testpage.
Following Process works totally:
Via CUPS webinterface at localhost:631 //the.ip. of.theprinter
Add a printer
Choose JetDirect
Apply socket:
Choose PPD file
Save.
Issue a testpage.
Now at least restart printer & cups and/or reboot computer.
Eventually cancel testpage and re-issue testpage.