6
7409 Restrictions for USB Devices if Using S3 Standby
If
S3
Standby
state
is
desired,
there
are
certain
restrictions
with
connecting
the
MSR
to
a
7409
terminal.
Restrictions on 7409 USB Ports:
If a Restricted Device is
plugged into Port:
An S3 Wake Device can
NOT be plugged into Port:
A
B
B
A
C
D
D
C
E
F
F
E
Note:
The
restrictions
only
apply
if
it
is
desired
to
put
the
unit
in
S3
standby
state.
USB Devices Capable of Waking the 7409 from an S3 State
•
USB
Keyboard
•
USB
Mouse
Reasons for the Restrictions
•
USB
ports
share
UHCI
host
controllers
in
the
Southbridge.
•
All
external
USB
ports
on
the
7409
are
powered
by
5VSB
and
kept
ON
during
S3
Standby.
•
Some
USB
peripherals
are
powered
by
the
RS
‐
232
port
(either
5V
or
12V).
Ways Around the Issue
•
Adhere
to
the
Restriction
Guidelines
provided
above.
•
In
Windows,
disable
the
S3
Wake
Device’s
ability
to
wake
the
unit
from
Standby.
•
Power
the
Restricted
Devices
from
an
external
power
source
instead
of
the
RS
‐
232
ports.
