The
rtfps driver provides support for IBM RT PC boards that multiplex together up to four EIA RS-232C (CCITT V.28) or RS-422A communications interfaces.
Each
rtfps device is the master device for up to four
com devices. The kernel configuration specifies these
com devices as slave devices of the
rtfps device, as shown in the synopsis. The port specification for the
rtfps device is used to compute the base addresses for the
com subdevices.