stty hardware flow control

[Sven Dietrich]

 I tried this many times: when I type

  stty -n /dev/tty0 flow 

 (this should be correct syntax according to the man page)

in order to enable hardware flow control between my modem and MacIIfx, I get
the strange result:

stty: :Invalid argument

 What am I doing wrong? My setup:

 Mac IIfx with 8 MB, A/UX 2.0, 80MB drive internal, serial port has a
USR Dual Std HST attached to it and is locked at 38400 baud.