rts/cts flow control

[Jeff Stearns]

In article <338 at proton.UUCP> proton!nusbaum at ucsd.edu (R. James Nusbaum)
writes:

: Do Sun 3s support rts/cts flow control on the built in serial ports?  The
: manuals seem to suggest that they don't (they tell you to enable xon/xoff
: and loop back the rts/cts wires), but there is an undocumented switch to
: stty, crtscts, that probably is meant to turn the hardware flow control on
: and off.

The following is extracted from the 4.0.1 manual.  I have elided some
paragraphs for brevity.  If you do upgrade, be sure to install the "Serial
Port Patch Tape" before proceeding.


ZS(4S)           DEVICES AND NETWORK INTERFACES            ZS(4S)

NAME
     zs - Zilog 8530 SCC serial communications driver

DESCRIPTION
     The Zilog 8530 provides 2 serial  communication  ports  with
     full modem control in asynchronous mode.  Each port supports
     those termio(4) device control functions specified by  flags
     in  the  c_cflag  word  of  the termios structure and by the
     IGNBRK, IGNPAR, PARMRK, or INPCK flags in the  c_iflag  word
     of  the  termios  structure  are performed by the zs driver.

     Of the synopsis lines above, the line for zs0 specifies  the
     serial  I/O  port(s) provided by the CPU board, the line for
     zs1 specifies the Video Board ports (which are used for key-
     board  and  mouse),  the  lines  for zs2 and zs3 specify the
     first and second ports on the first SCSI board in a  system,
     and those for zs4 and zs5 specify the first and second ports
     provided by the second SCSI board in a system, respectively.

     Bit i of flags may be specified to say that a  line  is  not
     properly connected, and that the line i should be treated as
     hard-wired with carrier  always  present.   Thus  specifying
     flags  0x2  in  the  specification  of  zs0 would treat line
     /dev/ttyb in this way.

IOCTLS
     The standard set of termio ioctl() calls  are  supported  by
     zs.

     If the CRTSCTS flag in the c_cflag is set,  output  will  be
     generated only if CTS is high; if CTS is low, output will be
     frozen.   If the CRTSCTS flag is clear, the state of CTS has
     no effect.  Breaks can be generated by the TCSBRK, TIOCSBRK,
     and  TIOCCBRK  ioctl()  calls.   The  modem  control   lines
     TIOCM_CAR, TIOCM_CTS, TIOCM_RTS, and TIOCM_DTR are provided.

    Jeff Stearns        John Fluke Mfg. Co, Inc.               (206) 356-5064
    jeff at tc.fluke.COM   {uw-beaver,microsoft,sun}!fluke!jeff

PS - Calling all users of the Vitalink TransLAN IV Ethernet bridge! Please
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