<s>
Turbo	B-Device
SIM	I-Device
card	O
(	O
also	O
known	O
as	O
TurboSIM	B-Device
or	O
Unlock	O
Chip	O
)	O
is	O
considered	O
to	O
be	O
the	O
forerunner	O
of	O
a	O
large	O
family	O
of	O
"	O
Dual	O
SIM	O
"	O
devices	O
(	O
X-SIM	O
,	O
R-SIM	O
,	O
HyperCard	O
,	O
HyperSIM	O
,	O
China3GPP	O
,	O
StealthSim	O
,	O
MagicSIM	O
,	O
etc	O
.	O
)	O
</s>
<s>
Without	O
the	O
TurboSIM	B-Device
,	O
the	O
original	O
SIM	O
card	O
is	O
usable	O
as	O
before	O
.	O
</s>
<s>
The	O
Turbo	B-Device
SIM	I-Device
is	O
claimed	O
to	O
work	O
with	O
any	O
GSM	O
mobile	O
phone	O
produced	O
since	O
1998	O
,	O
and	O
can	O
be	O
used	O
to	O
add	O
new	O
functionality	O
such	O
as	O
larger	O
SMS	B-Device
archives	O
to	O
some	O
phones	O
.	O
</s>
<s>
This	O
device	O
,	O
and	O
those	O
like	O
it	O
,	O
use	O
a	O
small	O
microcontroller	O
(	O
the	O
original	O
Turbo	B-Device
SIM	I-Device
used	O
an	O
Atmel	O
ATmega128	O
)	O
to	O
intercept	O
traffic	O
between	O
the	O
cell	O
phone	O
and	O
the	O
original	O
SIM	O
card	O
,	O
and	O
modify	O
this	O
traffic	O
based	O
on	O
programming	O
stored	O
in	O
the	O
microcontroller	O
.	O
</s>
<s>
The	O
most	O
common	O
purpose	O
of	O
the	O
Turbo	B-Device
SIM	I-Device
is	O
to	O
spoof	O
the	O
IMSI	O
number	O
and	O
authentication	O
key	O
(	O
Ki	O
)	O
supplied	O
by	O
the	O
SIM	O
card	O
to	O
the	O
network	O
,	O
allowing	O
phones	O
locked	O
to	O
use	O
only	O
a	O
particular	O
network	O
(	O
SIM	O
locked	O
)	O
such	O
as	O
the	O
Apple	O
iPhone	B-Device
,	O
and	O
more	O
recently	O
NTT	O
DoCoMo	O
and	O
SoftBank	O
phones	O
,	O
to	O
be	O
used	O
on	O
any	O
mobile	O
network	O
with	O
which	O
they	O
are	O
technically	O
compatible	O
.	O
</s>
<s>
The	O
legal	O
status	O
of	O
using	O
a	O
TurboSIM	B-Device
or	O
an	O
Unlock	O
Chip	O
is	O
affected	O
by	O
laws	O
regarding	O
circumvention	O
of	O
digital	O
locks	O
,	O
such	O
as	O
laws	O
protecting	O
digital	O
rights	O
management	O
(	O
DRM	O
)	O
mechanisms	O
.	O
</s>
<s>
However	O
,	O
many	O
countries	O
do	O
not	O
have	O
such	O
laws	O
,	O
and	O
some	O
countries	O
have	O
laws	O
including	O
exceptions	O
for	O
the	O
use	O
of	O
TurboSIM	B-Device
.	O
</s>
