The physical device driver provides no data translation, code page, or monitor support. It is the responsibility of the application or subsystem to provide any function required in these areas.

Spooling from LPT to COM is supported by the spooler, but spooling from COM to LPT, or COM to COM, is not supported. When spooling from COM to LPT, code page support is provided by the spooler.

Any requests for registering or opening a monitor chain to COMn are rejected by the physical device driver. The physical device driver deals with binary data and provides no special processing of binary or ASCII data streams.