diff --git a/sim_console.c b/sim_console.c
index fc35d801..bea49c75 100644
--- a/sim_console.c
+++ b/sim_console.c
@@ -3928,6 +3928,12 @@ return SCPE_OK;
 
 #else
 
+#if !defined(CANT_USE_TERMIOS_TCSAFLUSH)
+#define TCSETATTR_ACTION TCSAFLUSH
+#else
+#define TCSETATTR_ACTION TCSANOW
+#endif
+
 #include <termios.h>
 #include <unistd.h>
 
@@ -3988,7 +3994,7 @@ runtty.c_cc[VINTR] = 0;                                 /* OS X doesn't deliver
 #else
 runtty.c_cc[VINTR] = sim_int_char;                      /* in case changed */
 #endif
-if (tcsetattr (fileno(stdin), TCSAFLUSH, &runtty) < 0)
+if (tcsetattr (fileno(stdin), TCSETATTR_ACTION, &runtty) < 0)
     return SCPE_TTIERR;
 sim_os_set_thread_priority (PRIORITY_BELOW_NORMAL);     /* try to lower pri */
 return SCPE_OK;
@@ -3999,7 +4005,7 @@ static t_stat sim_os_ttcmd (void)
 if (!isatty (fileno (stdin)))                           /* skip if !tty */
     return SCPE_OK;
 sim_os_set_thread_priority (PRIORITY_NORMAL);           /* try to raise pri */
-if (tcsetattr (fileno(stdin), TCSAFLUSH, &cmdtty) < 0)
+if (tcsetattr (fileno(stdin), TCSETATTR_ACTION, &cmdtty) < 0)
     return SCPE_TTIERR;
 return SCPE_OK;
 }