stty bugs

Hello,

I thing that something is wrong with stty command this are listings from =
Cygwin:

$ stty -F /dev/com1
speed 9600 baud; line =3D 0;
intr =3D <undef>; quit =3D <undef>; erase =3D <undef>; kill =3D <undef>; =
eof =3D <undef>;
susp =3D <undef>; rprnt =3D <undef>; werase =3D <undef>; lnext =3D =
<undef>;
flush =3D <undef>; min =3D 0; time =3D 0;
-cread
-brkint -icrnl -imaxbel
-opost -onlcr
-isig -icanon -iexten -echo -echoe -echok -echoctl -echoke
$

(Then i try to start the reciver)

$ stty -F /dev/com1 cread
stty: /dev/com1: unable to perform all requested operations
$
What dose it means ? Why i can't  start reciver ? I have big problem =
with modem communication.

Artur Bednarski