OS:

The Panasonic Sr. Partner shipped with an OEM version of MS-DOS 2.x.
Any generic MS-DOS 2.x is an acceptable substitute.

The file SPARTNER.ZIP contains files from a supplimental disk that contains
a demo, a terminal program, and most importantly diagnositcs (see DIAG.COM below).

DIAGS:

The ROM of the Panasonic Sr. Partner contains a built-in diagnostic.
You can launch into it by setting AH to 82h and then INT 18h.
However, it appears to need the DIAG.COM file to properly configure it.

Internal printer appears compatible with the Epson MX 80.

The German Nixdorf manual says:
Spezielle Tasten für den Drucker
SHIFT + PrtSc   Druckt den Bildschirminhalt aus.
CTRL + PrtSc    Druckt das.was eingegeben wird
ALT + Esc       Setzt den Drucker zurück.
Alt + PrtSc     Schaltet um auf einen externen Drucker.

Translated, that means:
Special buttons for the printer:
SHIFT + PrtSc   Prints the screen space
CTRL + PrtSc    Prints what is entered
ALT + Esc       Resets the printer
Alt + PrtSc     Switches to an external printer


There is a small single dip switch inside of where the paper goes.
If set to ON, it causes the printer to print a blank line after every printed line.