<s>
A	O
KVM	B-Device
switch	I-Device
(	O
with	O
KVM	B-Application
being	O
an	O
abbreviation	O
for	O
"	O
keyboard	B-Device
,	O
video	O
,	O
and	O
mouse	O
"	O
)	O
is	O
a	O
hardware	B-Architecture
device	O
that	O
allows	O
a	O
user	O
to	O
control	O
multiple	O
computers	O
from	O
one	O
or	O
more	O
sets	O
of	O
keyboards	B-Device
,	O
video	B-Device
monitors	I-Device
,	O
and	O
mice	B-Device
.	O
</s>
<s>
Switches	B-Device
to	O
connect	O
multiple	O
computers	O
to	O
one	O
or	O
more	O
peripherals	O
have	O
had	O
a	O
variety	O
of	O
names	O
.	O
</s>
<s>
The	O
earliest	O
name	O
was	O
Keyboard	B-Device
Video	O
Switch	O
(	O
KVS	O
)	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
the	O
mouse	O
,	O
the	O
Keyboard	B-Device
,	O
Video	O
and	O
Mouse	O
(	O
KVM	B-Application
)	O
switch	O
became	O
popular	O
.	O
</s>
<s>
Some	O
companies	O
call	O
their	O
switches	B-Device
Keyboard	B-Device
,	O
Video	O
,	O
Mouse	O
and	O
Peripheral	O
(	O
KVMP	O
)	O
.	O
</s>
<s>
With	O
the	O
popularity	O
of	O
USB	B-Protocol
—	O
USB	B-Protocol
keyboards	B-Device
,	O
mice	B-Device
,	O
and	O
I/O	O
devices	O
are	O
still	O
the	O
most	O
common	O
devices	O
connected	O
to	O
a	O
KVM	B-Device
switch	I-Device
.	O
</s>
<s>
The	O
classes	O
of	O
KVM	B-Device
switches	I-Device
that	O
are	O
reviewed	O
,	O
are	O
based	O
on	O
different	O
types	O
of	O
core	O
technologies	O
in	O
terms	O
of	O
how	O
the	O
KVM	B-Device
switch	I-Device
handles	O
USB	B-Protocol
I/O	O
devices	O
—	O
including	O
keyboards	B-Device
,	O
mice	B-Device
,	O
touchscreen	O
displays	O
,	O
etc	O
.	O
</s>
<s>
USB	B-Protocol
Hub	O
Based	O
KVMAlso	O
called	O
an	O
Enumerated	O
KVM	B-Device
switch	I-Device
or	O
USB	B-Protocol
switch	O
selector	O
,	O
a	O
connected/shared	O
USB	B-Protocol
device	O
must	O
go	O
through	O
the	O
full	O
initiation	O
process	O
(	O
USB	B-Protocol
enumeration	O
)	O
every	O
time	O
the	O
KVM	B-Application
is	O
switched	O
to	O
another	O
target	O
system/port	O
.	O
</s>
<s>
The	O
switching	O
to	O
different	O
ports	O
is	O
just	O
as	O
if	O
you	O
were	O
to	O
physically	O
plug	O
and	O
unplug	O
a	O
USB	B-Protocol
device	O
into	O
your	O
targeted	O
system	O
.	O
</s>
<s>
Emulated	O
USB	B-Protocol
KVM	B-Application
Dedicated	O
USB	B-Protocol
console	O
port(s )	O
are	O
assigned	O
to	O
emulate	O
special	O
sets	O
of	O
USB	B-Protocol
keyboard	B-Device
or	O
mouse	O
switching	O
control	O
information	O
to	O
each	O
connected/targeted	O
system	O
.	O
</s>
<s>
Emulated	O
USB	B-Protocol
provides	O
an	O
instantaneous	O
and	O
reliable	O
switching	O
action	O
that	O
makes	O
keyboard	B-Device
hotkeys	O
and	O
mouse	O
switching	O
possible	O
.	O
</s>
<s>
However	O
,	O
this	O
class	O
of	O
KVM	B-Device
switch	I-Device
only	O
uses	O
generic	O
emulations	O
and	O
consequently	O
has	O
only	O
been	O
able	O
to	O
support	O
the	O
most	O
basic	O
keyboard	B-Device
and	O
mouse	O
features	O
.	O
</s>
<s>
There	O
are	O
also	O
USB	B-Protocol
KVM	B-Application
devices	O
that	O
allow	O
cross-platform	O
operating	O
systems	O
and	O
basic	O
keyboard	B-Device
and	O
mouse	O
sharing	O
.	O
</s>
<s>
Semi-DDM	O
USB	B-Protocol
KVM	B-Application
Dedicated	O
USB	B-Protocol
console	O
port(s )	O
work	O
with	O
all	O
USB-HID	O
(	O
including	O
keyboard	B-Device
and	O
mouse	O
)	O
,	O
but	O
do	O
not	O
maintain	O
the	O
connected	O
devices	O
 '	O
presence	O
to	O
all	O
of	O
the	O
targeted	O
systems	O
simultaneously	O
.	O
</s>
<s>
This	O
class	O
of	O
KVM	B-Application
takes	O
advantage	O
of	O
DDM	O
(	O
Dynamic	B-Device
Device	I-Device
Mapping	I-Device
)	O
.	O
</s>
<s>
DDM	O
USB	B-Protocol
KVM	B-Application
Dedicated	O
Dynamic	B-Device
device	I-Device
mapping	I-Device
USB	B-Protocol
console	O
port(s )	O
work	O
with	O
all	O
USB-HID	O
(	O
including	O
keyboard	B-Device
and	O
mouse	O
)	O
and	O
maintain	O
the	O
connected	O
devices	O
 '	O
special	O
functions	O
and	O
characteristics	O
to	O
each	O
connected/targeted	O
system	O
.	O
</s>
<s>
This	O
class	O
of	O
KVM	B-Device
switch	I-Device
overcomes	O
the	O
frustrating	O
limitations	O
of	O
an	O
Emulated	O
USB	B-Protocol
Class	O
KVM	B-Application
by	O
emulating	O
the	O
true	O
characters	O
of	O
the	O
connected	O
devices	O
to	O
all	O
the	O
computers	O
simultaneously	O
.	O
</s>
<s>
This	O
means	O
that	O
you	O
can	O
now	O
use	O
the	O
extra	O
function	O
keys	O
,	O
wheels	O
,	O
buttons	O
,	O
and	O
controls	O
that	O
are	O
commonly	O
found	O
on	O
modern	O
keyboards	B-Device
and	O
mice	B-Device
.	O
</s>
<s>
Feature	O
Hub	O
Base	O
Class	O
Emulated	O
Class	O
Semi-DDM	O
Class	O
DDM	O
Class	O
USB	B-Protocol
re-enumeration	O
required	O
Latency	O
in	O
sharing	O
connected	O
USB	B-Protocol
devices	O
Short	O
Short	O
Supports	O
Hot-Key	O
Command	O
,	O
only	O
on	O
dedicated	O
keyboard	B-Device
port	O
,	O
all	O
the	O
console	O
Semi-DDM	O
ports	O
,	O
all	O
the	O
console	O
DDM	O
ports	O
Supports	O
special	O
keyboard	B-Device
and	O
mouse	O
functions	O
Limited*	O
,	O
only	O
acts	O
as	O
standard	O
keyboard/mouse	O
Windows	O
7/Windows	O
8	O
showing	O
correct	O
connected	O
devices	O
Limited*	O
,	O
shows	O
as	O
standard	O
keyboard	B-Device
and	O
mouse	O
no	O
matter	O
what	O
keyboard/mouse	O
are	O
connected	O
to	O
the	O
KVM	B-Application
Windows7/Windows	O
8	O
built-in	O
touchscreen	O
monitor	O
driver	O
support	O
Limited*	O
*	O
Wireless	O
combo	O
keyboard	B-Device
and	O
mouse	O
support	O
Limited*	O
*	O
USB-HID	O
(	O
other	O
than	O
keyboard/mouse	O
)	O
support	O
Limited*	O
*	O
USB	B-Protocol
touchscreen	O
sharing	O
support	O
Limited*	O
*	O
Drawing	O
tablet	B-Device
support	O
Limited*	O
*	O
USB	B-Protocol
wireless	O
unifying	O
receiver	O
support	O
Limited*	O
*	O
Pros	O
Passes	O
all	O
signals	O
between	O
USB	B-Protocol
devices	O
and	O
target	O
system/computer	O
( s	O
)	O
USB	B-Protocol
keyboard/mouse	O
switching	O
control	O
,	O
shorter	O
switching	O
time	O
,	O
Hot-Key	O
Commands	O
Full	O
USB	B-Protocol
keyboard/mouse	O
switching	O
control	O
,	O
DDM	O
ports	O
can	O
work	O
with	O
all	O
USB-HID	O
class	O
devices	O
,	O
Short	O
switching	O
time	O
(	O
latency	O
:	O
within	O
1	O
sec	O
.	O
</s>
<s>
Limited*supported	O
,	O
but	O
does	O
not	O
allow	O
USB	B-Protocol
re-enumeration	O
,	O
which	O
not	O
only	O
causes	O
long	O
delays	O
in	O
switching	O
,	O
but	O
also	O
sometimes	O
causes	O
HPD	O
(	O
Hot-Plug	O
Device	O
)	O
errors	O
to	O
the	O
OS	O
system(s )	O
.	O
</s>
<s>
A	O
KVM	B-Device
Switch	I-Device
is	O
a	O
hardware	B-Architecture
device	O
,	O
used	O
in	O
data	B-Operating_System
centers	I-Operating_System
,	O
that	O
allows	O
the	O
control	O
of	O
multiple	O
computers	O
from	O
a	O
single	O
keyboard	B-Device
,	O
monitor	O
and	O
mouse	O
(	O
KVM	B-Application
)	O
.	O
</s>
<s>
This	O
switch	O
then	O
allows	O
data	B-Operating_System
center	I-Operating_System
personnel	O
to	O
connect	O
to	O
any	O
server	O
in	O
the	O
rack	O
.	O
</s>
<s>
A	O
common	O
example	O
of	O
home	O
use	O
is	O
to	O
enable	O
the	O
use	O
of	O
the	O
full-size	O
keyboard	B-Device
,	O
mouse	O
and	O
monitor	O
of	O
the	O
home	O
PC	O
with	O
a	O
portable	O
device	O
such	O
as	O
a	O
laptop	O
,	O
tablet	B-Device
PC	I-Device
or	O
PDA	B-Application
,	O
or	O
a	O
computer	O
using	O
a	O
different	O
operating	O
system	O
.	O
</s>
<s>
KVM	B-Device
switches	I-Device
offer	O
different	O
methods	O
of	O
connecting	O
the	O
computers	O
.	O
</s>
<s>
Depending	O
on	O
the	O
product	O
,	O
the	O
switch	O
may	O
present	O
native	O
connectors	O
on	O
the	O
device	O
where	O
standard	O
keyboard	B-Device
,	O
monitor	O
and	O
mouse	O
cables	O
can	O
be	O
attached	O
.	O
</s>
<s>
Another	O
method	O
to	O
have	O
a	O
single	O
DB25	B-Protocol
or	O
similar	O
connector	O
that	O
aggregated	O
connections	O
at	O
the	O
switch	O
with	O
three	O
independent	O
keyboard	B-Device
,	O
monitor	O
and	O
mouse	O
cables	O
to	O
the	O
computers	O
.	O
</s>
<s>
Subsequently	O
,	O
these	O
were	O
replaced	O
by	O
a	O
special	O
KVM	B-Device
cable	I-Device
which	O
combined	O
the	O
keyboard	B-Device
,	O
video	O
and	O
mouse	O
cables	O
in	O
a	O
single	O
wrapped	O
extension	O
cable	O
.	O
</s>
<s>
The	O
advantage	O
of	O
the	O
last	O
approach	O
is	O
in	O
the	O
reduction	O
of	O
the	O
number	O
of	O
cables	O
between	O
the	O
KVM	B-Device
switch	I-Device
and	O
connected	O
computers	O
.	O
</s>
<s>
The	O
original	O
peripheral	O
switches	B-Device
(	O
Rose	O
,	O
circa	O
1988	O
)	O
used	O
a	O
rotary	O
switch	O
while	O
active	O
electronic	O
switches	B-Device
(	O
Cybex	O
,	O
circa	O
1990	O
)	O
used	O
push	O
buttons	O
on	O
the	O
KVM	B-Application
device	O
.	O
</s>
<s>
In	O
both	O
cases	O
,	O
the	O
KVM	B-Application
aligns	O
operation	O
between	O
different	O
computers	O
and	O
the	O
users	O
 '	O
keyboard	B-Device
,	O
monitor	O
and	O
mouse	O
(	O
user	O
console	O
)	O
.	O
</s>
<s>
In	O
1992	O
–	O
1993	O
,	O
Cybex	O
Corporation	O
engineered	O
keyboard	B-Device
hot-key	O
commands	O
.	O
</s>
<s>
Today	O
,	O
most	O
KVMs	B-Application
are	O
controlled	O
through	O
non-invasive	O
hot-key	O
commands	O
(	O
e.g.	O
</s>
<s>
KVM	B-Device
switches	I-Device
differ	O
in	O
the	O
number	O
of	O
computers	O
that	O
can	O
be	O
connected	O
.	O
</s>
<s>
Enterprise-grade	O
devices	O
interconnected	O
via	O
daisy-chained	B-Application
and/or	O
cascaded	O
methods	O
can	O
support	O
a	O
total	O
of	O
512	O
computers	O
equally	O
accessed	O
by	O
any	O
given	O
user	O
console	O
.	O
</s>
<s>
While	O
HDMI	B-Protocol
,	O
DisplayPort	B-Protocol
,	O
and	O
DVI	B-Protocol
switches	B-Device
have	O
been	O
manufactured	O
,	O
VGA	B-Protocol
is	O
still	O
the	O
most	O
common	O
video	O
connector	O
found	O
with	O
KVM	B-Device
switches	I-Device
,	O
although	O
many	O
switches	B-Device
are	O
now	O
compatible	O
with	O
DVI	B-Protocol
connectors	I-Protocol
.	O
</s>
<s>
Analogue	O
switches	B-Device
can	O
be	O
built	O
with	O
varying	O
capacities	O
for	O
video	O
bandwidth	O
,	O
affecting	O
the	O
unit	O
's	O
overall	O
cost	O
and	O
quality	O
.	O
</s>
<s>
The	O
method	O
of	O
converting	O
these	O
factors	O
into	O
bandwidth	O
requirements	O
is	O
a	O
point	O
of	O
ambiguity	O
,	O
in	O
part	O
because	O
it	O
is	O
dependent	O
on	O
the	O
analogue	O
nature	O
and	O
state	O
of	O
the	O
hardware	B-Architecture
.	O
</s>
<s>
As	O
CRT-based	O
displays	O
are	O
dependent	O
on	O
refresh	O
rate	O
to	O
prevent	O
flickering	O
,	O
they	O
generally	O
require	O
more	O
bandwidth	O
than	O
comparable	O
flat	O
panel	O
displays	O
.	O
</s>
<s>
A	O
monitor	O
uses	O
DDC	O
and	O
EDID	B-General_Concept
,	O
transmitted	O
through	O
specific	O
pins	O
,	O
to	O
identify	O
itself	O
to	O
the	O
system	O
.	O
</s>
<s>
KVM	B-Device
switches	I-Device
may	O
have	O
different	O
ways	O
of	O
handling	O
these	O
data	O
transmissions	O
:	O
</s>
<s>
None	O
:	O
the	O
KVM	B-Device
switch	I-Device
lacks	O
the	O
circuitry	O
to	O
handle	O
this	O
data	O
,	O
and	O
the	O
monitor	O
is	O
not	O
"	O
visible	O
"	O
to	O
the	O
system	O
.	O
</s>
<s>
However	O
,	O
certain	O
applications	O
(	O
especially	O
games	O
)	O
that	O
depend	O
on	O
retrieving	O
DDC/EDID	O
information	O
will	O
not	O
be	O
able	O
to	O
function	O
correctly	O
.	O
</s>
<s>
Fake	O
:	O
the	O
KVM	B-Device
switch	I-Device
generates	O
its	O
own	O
DDC/EDID	O
information	O
that	O
may	O
or	O
may	O
not	O
be	O
appropriate	O
for	O
the	O
monitor	O
that	O
is	O
attached	O
.	O
</s>
<s>
Problems	O
may	O
arise	O
if	O
there	O
is	O
an	O
inconsistency	O
between	O
the	O
KVM	B-Application
's	O
specifications	O
and	O
the	O
monitor	O
's	O
,	O
such	O
as	O
not	O
being	O
able	O
to	O
select	O
desired	O
resolutions	O
.	O
</s>
<s>
Pass-through	O
:	O
the	O
KVM	B-Device
switch	I-Device
attempts	O
to	O
make	O
communication	O
between	O
the	O
monitor	O
and	O
the	O
system	O
transparent	O
.	O
</s>
<s>
Microsoft	O
guidelines	O
recommend	O
that	O
KVM	B-Device
switches	I-Device
pass	O
unaltered	O
any	O
I2C	O
traffic	O
between	O
the	O
monitor	O
and	O
the	O
PC	O
hosts	O
,	O
and	O
do	O
not	O
generate	O
HPD	O
events	O
upon	O
switching	O
to	O
a	O
different	O
port	O
while	O
maintaining	O
stable	O
non-noise	O
signal	O
on	O
inactive	O
ports	O
.	O
</s>
<s>
KVM	B-Device
switches	I-Device
were	O
originally	O
passive	O
,	O
mechanical	O
devices	O
based	O
on	O
multi-pole	O
switches	B-Device
and	O
some	O
of	O
the	O
cheapest	O
devices	O
on	O
the	O
market	O
still	O
use	O
this	O
technology	O
.	O
</s>
<s>
Mechanical	O
switches	B-Device
usually	O
have	O
a	O
rotary	O
knob	O
to	O
select	O
between	O
computers	O
.	O
</s>
<s>
KVMs	B-Application
typically	O
allow	O
sharing	O
of	O
two	O
or	O
four	O
computers	O
,	O
with	O
a	O
practical	O
limit	O
of	O
about	O
twelve	O
machines	O
imposed	O
by	O
limitations	O
on	O
available	O
switch	O
configurations	O
.	O
</s>
<s>
Modern	O
hardware	B-Architecture
designs	O
use	O
active	O
electronics	O
rather	O
than	O
physical	O
switch	O
contacts	O
with	O
the	O
potential	O
to	O
control	O
many	O
computers	O
on	O
a	O
common	O
system	O
backbone	O
.	O
</s>
<s>
One	O
limitation	O
of	O
mechanical	O
KVM	B-Device
switches	I-Device
is	O
that	O
any	O
computer	O
not	O
currently	O
selected	O
by	O
the	O
KVM	B-Device
switch	I-Device
does	O
not	O
'	O
see	O
 '	O
a	O
keyboard	B-Device
or	O
mouse	O
connected	O
to	O
it	O
.	O
</s>
<s>
In	O
normal	O
operation	O
this	O
is	O
not	O
a	O
problem	O
,	O
but	O
while	O
the	O
machine	O
is	O
booting	O
up	O
it	O
will	O
attempt	O
to	O
detect	O
its	O
keyboard	B-Device
and	O
mouse	O
and	O
either	O
fail	O
to	O
boot	O
or	O
boot	O
with	O
an	O
unwanted	O
(	O
e.g.	O
</s>
<s>
Thus	O
,	O
mechanical	O
KVM	B-Device
switches	I-Device
may	O
be	O
unsuitable	O
for	O
controlling	O
machines	O
which	O
can	O
reboot	O
automatically	O
(	O
e.g.	O
</s>
<s>
Most	O
active	O
(	O
electronic	O
rather	O
than	O
mechanical	O
)	O
KVM	B-Application
devices	O
provide	O
peripheral	O
emulation	O
,	O
sending	O
signals	O
to	O
the	O
computers	O
that	O
are	O
not	O
currently	O
selected	O
to	O
simulate	O
a	O
keyboard	B-Device
,	O
mouse	O
and	O
monitor	O
being	O
connected	O
.	O
</s>
<s>
Peripheral	O
emulation	O
services	O
embedded	O
in	O
the	O
hardware	B-Architecture
also	O
provides	O
continuous	O
support	O
where	O
computers	O
require	O
constant	O
communication	O
with	O
the	O
peripherals	O
.	O
</s>
<s>
Some	O
types	O
of	O
active	O
KVM	B-Device
switches	I-Device
do	O
not	O
emit	O
signals	O
that	O
exactly	O
match	O
the	O
physical	O
keyboard	B-Device
,	O
monitor	O
,	O
and	O
mouse	O
,	O
which	O
can	O
result	O
in	O
unwanted	O
behavior	O
of	O
the	O
controlled	O
machines	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
user	O
of	O
a	O
multimedia	O
keyboard	B-Device
connected	O
to	O
a	O
KVM	B-Device
switch	I-Device
may	O
find	O
that	O
the	O
keyboard	B-Device
's	O
multimedia	O
keys	O
have	O
no	O
effect	O
on	O
the	O
controlled	O
computers	O
.	O
</s>
<s>
There	O
are	O
software	O
alternatives	O
to	O
some	O
of	O
the	O
functionality	O
of	O
a	O
hardware	B-Architecture
KVM	B-Device
switch	I-Device
,	O
such	O
as	O
Multiplicity	B-Device
,	O
Synergy	B-Language
,	O
and	O
Barrier	B-Device
,	O
which	O
does	O
the	O
switching	O
in	O
software	O
and	O
forwards	O
input	O
over	O
standard	O
network	O
connections	O
.	O
</s>
<s>
There	O
are	O
two	O
types	O
of	O
remote	O
KVM	B-Application
devices	O
that	O
are	O
best	O
described	O
as	O
local	O
remote	O
and	O
KVM	B-Application
over	O
IP	O
.	O
</s>
<s>
Local	O
remote	O
KVM	B-Application
device	O
design	O
allows	O
users	O
to	O
control	O
computer	O
equipment	O
up	O
to	O
away	O
from	O
the	O
user	O
consoles	O
(	O
keyboard	B-Device
,	O
monitor	O
and	O
mouse	O
)	O
.	O
</s>
<s>
They	O
always	O
need	O
direct	O
cable	O
connection	O
from	O
the	O
computer	O
to	O
the	O
KVM	B-Device
switch	I-Device
to	O
the	O
console	O
and	O
include	O
support	O
for	O
standard	O
category	B-Protocol
5	I-Protocol
cabling	I-Protocol
between	O
computers	O
and	O
users	O
interconnected	O
by	O
the	O
switch	O
device	O
.	O
</s>
<s>
In	O
contrast	O
,	O
USB	B-Protocol
powered	O
KVM	B-Application
devices	O
are	O
able	O
to	O
control	O
computer	O
equipment	O
using	O
a	O
combination	O
of	O
USB	B-Protocol
,	O
keyboard	B-Device
,	O
mouse	O
and	O
monitor	O
cables	O
of	O
up	O
to	O
.	O
</s>
<s>
KVM	B-Device
switch	I-Device
over	O
IP	O
devices	O
use	O
a	O
dedicated	O
micro-controller	O
and	O
potentially	O
specialized	O
video	O
capture	O
hardware	B-Architecture
to	O
capture	O
the	O
video	O
,	O
keyboard	B-Device
,	O
and	O
mouse	O
signals	O
,	O
compress	O
and	O
convert	O
them	O
into	O
packets	O
,	O
and	O
send	O
them	O
over	O
an	O
Ethernet	O
link	O
to	O
a	O
remote	O
console	O
application	O
that	O
unpacks	O
and	O
reconstitutes	O
the	O
dynamic	O
graphical	O
image	O
.	O
</s>
<s>
KVM	B-Application
over	O
IP	O
subsystem	O
is	O
typically	O
connected	O
to	O
a	O
system	O
's	O
standby	O
power	O
plane	O
so	O
that	O
it	O
's	O
available	O
during	O
the	O
entire	O
BIOS	B-Operating_System
boot	O
process	O
.	O
</s>
<s>
There	O
are	O
performance	O
issues	O
related	O
with	O
LAN/WAN	O
hardware	B-Architecture
,	O
standard	O
protocols	O
and	O
network	O
latency	O
so	O
user	O
management	O
is	O
commonly	O
referred	O
to	O
as	O
"	O
near	O
real	O
time	O
"	O
.	O
</s>
<s>
Access	O
to	O
most	O
remote	O
or	O
"	O
KVM	B-Application
"	O
over	O
IP	O
devices	O
today	O
use	O
a	O
web	B-Application
browser	I-Application
,	O
although	O
many	O
of	O
the	O
stand-alone	O
viewer	O
software	O
applications	O
provided	O
by	O
many	O
manufacturers	O
are	O
also	O
reliant	O
on	O
ActiveX	B-Application
or	O
Java	B-Device
.	O
</s>
<s>
Some	O
KVM	B-Application
chipsets	O
or	O
manufacturers	O
require	O
the	O
"	O
whitelisting	O
"	O
or	O
authority	O
to	O
connect	O
to	O
be	O
implicitly	O
enabled	O
.	O
</s>
<s>
This	O
is	O
by	O
design	O
and	O
required	O
to	O
connect	O
non-standard	O
USB	B-Protocol
devices	O
to	O
KVMs	B-Application
.	O
</s>
<s>
This	O
is	O
completed	O
by	O
noting	O
the	O
device	O
's	O
ID	O
(	O
usually	O
copied	O
from	O
the	O
Device	O
manager	O
in	O
Windows	O
)	O
,	O
or	O
documentation	O
from	O
the	O
manufacturer	O
of	O
the	O
USB	B-Protocol
device	O
.	O
</s>
<s>
Generally	O
all	O
HID	O
or	O
consumer	O
grade	O
USB	B-Protocol
peripherals	O
are	O
exempt	O
,	O
but	O
more	O
exotic	O
devices	O
like	O
tablets	B-Device
,	O
or	O
digitisers	O
or	O
USB	B-Protocol
toggles	O
require	O
manual	O
addition	O
to	O
the	O
white	O
list	O
table	O
of	O
the	O
KVM	B-Application
.	O
</s>
<s>
In	O
comparison	O
to	O
conventional	O
methods	O
of	O
remote	O
administration	O
(	O
for	O
example	O
in-band	B-Application
Virtual	B-Protocol
Network	I-Protocol
Computing	I-Protocol
or	O
Terminal	B-Protocol
Services	I-Protocol
)	O
,	O
a	O
KVM	B-Device
switch	I-Device
has	O
the	O
advantage	O
that	O
it	O
does	O
n't	O
depend	O
on	O
a	O
software	O
component	O
running	O
on	O
the	O
remote	O
computer	O
,	O
thus	O
allowing	O
remote	O
interaction	O
with	O
base	O
level	O
BIOS	B-Operating_System
settings	I-Operating_System
and	O
monitoring	O
of	O
the	O
entire	O
booting	O
process	O
before	O
,	O
during	O
,	O
and	O
after	O
the	O
operating	O
system	O
loads	O
.	O
</s>
<s>
Modern	O
KVM	B-Application
over	O
IP	O
appliances	O
or	O
switches	B-Device
typically	O
use	O
at	O
least	O
128-bit	O
data	O
encryption	O
securing	O
the	O
KVM	B-Application
configuration	O
over	O
a	O
WAN	O
or	O
LAN	O
(	O
using	O
SSL	B-Protocol
)	O
.	O
</s>
<s>
KVM	B-Application
over	O
IP	O
devices	O
can	O
be	O
implemented	O
in	O
different	O
ways	O
.	O
</s>
<s>
With	O
regards	O
to	O
video	O
,	O
PCI	B-Protocol
KVM	B-Application
over	O
IP	O
cards	O
use	O
a	O
form	O
of	O
screen	O
scraping	O
where	O
the	O
PCI	B-Protocol
bus	I-Protocol
master	O
KVM	B-Application
over	O
IP	O
card	O
would	O
access	O
and	O
copy	O
out	O
the	O
screen	O
directly	O
from	O
the	O
graphics	O
memory	O
buffer	O
,	O
and	O
as	O
a	O
result	O
it	O
must	O
know	O
which	O
graphics	O
chip	O
it	O
is	O
working	O
with	O
,	O
and	O
what	O
graphics	O
mode	O
this	O
chip	O
is	O
currently	O
in	O
so	O
that	O
the	O
contents	O
of	O
the	O
buffer	O
can	O
be	O
interpreted	O
correctly	O
as	O
picture	O
data	O
.	O
</s>
<s>
Newer	O
techniques	O
in	O
OPMA	O
management	O
subsystem	O
cards	O
and	O
other	O
implementations	O
get	O
the	O
video	O
data	O
directly	O
using	O
the	O
DVI	B-Protocol
bus	O
.	O
</s>
<s>
Implementations	O
can	O
emulate	O
either	O
PS/2	B-Protocol
or	O
USB	B-Protocol
based	O
keyboards	B-Device
and	O
mice	B-Device
.	O
</s>
<s>
An	O
embedded	O
VNC	B-Protocol
server	I-Protocol
is	O
typically	O
used	O
for	O
the	O
video	O
protocol	O
in	O
IPMI	O
and	O
Intel	B-Application
AMT	I-Application
implementations	O
.	O
</s>
<s>
KVM	B-Device
switches	I-Device
are	O
called	O
KVM	B-Application
sharing	O
devices	O
because	O
two	O
or	O
more	O
computers	O
can	O
share	O
a	O
single	O
set	O
of	O
KVM	B-Application
peripherals	O
.	O
</s>
<s>
Computer	O
sharing	O
devices	O
function	O
in	O
reverse	O
compared	O
to	O
KVM	B-Device
switches	I-Device
;	O
that	O
is	O
,	O
a	O
single	O
PC	O
can	O
be	O
shared	O
by	O
multiple	O
monitors	O
,	O
keyboards	B-Device
,	O
and	O
mice	B-Device
.	O
</s>
<s>
A	O
computer	O
sharing	O
device	O
is	O
sometimes	O
referred	O
to	O
as	O
a	O
KVM	B-Protocol
Splitter	I-Protocol
or	O
reverse	O
KVM	B-Device
switch	I-Device
.	O
</s>
