diff --git a/src/os_unix.c b/src/os_unix.c
index da7f56a..d155142 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -3766,7 +3766,8 @@
     {
 	// ~ICRNL enables typing ^V^M
 	// ~IXON disables CTRL-S stopping output, so that it can be mapped.
-	tnew.c_iflag &= ~(ICRNL | IXON);
+	tnew.c_iflag &= ~(ICRNL |
+		(T_XON == NULL || *T_XON == NUL ? IXON : 0));
 	tnew.c_lflag &= ~(ICANON | ECHO | ISIG | ECHOE
 # if defined(IEXTEN)
 		    | IEXTEN	    // IEXTEN enables typing ^V on SOLARIS