Do the Sun serial ports support RTS/CTS flow control?

        The serial port hardware can do CTS-based control of the flow of
        data *from* the Sun *out* the serial port automatically.  The
        tty driver option for that is the CRTSCTS option; it can be
        specified in:

                the "printcap" "ms" capability for a printer;

                in the "gettytab" "ms", "m0", "m1", or "m2" capabilities
                for a dial-in port;

                the "STTY=" option for a dial-out line for UUCP or "cu"
                [check the UUCP documentation for details];

        and can be specified with the "hf" capability in "/etc/remote"
        for "tip".

        The hardware cannot directly do RTS-based control of the flow of
        data *into* the Sun, and the software does not currently support
        controlling the flow of data into the Sun with RTS.

        NOTE: the EEPROM options in newer Suns do not affect the flow

        control performed by the OS; in fact, the OS ignores the
        "ttya-mode", "ttyb-mode", "ttya-rts-dtr-off", and
        "ttyb-rts-dtr-off" EEPROM options entirely.  You don't need to
        set them to change the way the OS handles the tty, and even if
        you do set them, it won't change the way the OS handles the tty.

	Sun has released a new jumbo tty patch 100513-04 for SunOS 4.1.2 
	and 4.1.3 that incorporates changes to the tty driver to
	support RTS/CTS handshaking. Anyone trying to get RTS/CTS
	handshaking to work should get this patch.

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