(afaik PRN is not a parallel port, but a pseudo device that is an alias for the true port (typically LPT or COM))
The printer unit is for TP compatibility so limited.
Can you redirect PRN to a COM port? (I never seen PRN as COM port)
I thought AUX was for COM ports.
PRN defaulted to the first parallel port.
AUX 1st serial port
PRN 1st parallel port
COM1 thru COM4 Serial ports
LPT1 thru LPT3 Parallel ports
CON Keyboard and screen
NUL Dummy (for testing)
But yes, printer.pp is very limited.