<s>
In	O
laptop	B-Device
computing	O
,	O
the	O
XJACK	B-Protocol
is	O
a	O
type	O
of	O
extendable	O
connector	O
or	O
antenna	O
for	O
a	O
type	O
II	O
PC	B-Architecture
card	I-Architecture
,	O
designed	O
by	O
the	O
Megahertz	O
subsidiary	O
of	O
3Com	O
.	O
</s>
<s>
When	O
not	O
in	O
use	O
,	O
the	O
XJACK	B-Protocol
retracts	O
into	O
the	O
PC	B-Architecture
card	I-Architecture
for	O
storage	O
.	O
</s>
<s>
The	O
XJACK	B-Protocol
was	O
originally	O
used	O
in	O
modem	O
and	O
network	O
cards	O
,	O
to	O
attach	O
a	O
standard	O
RJ11	B-Protocol
or	O
8P8C	O
plug	O
directly	O
to	O
the	O
PC	B-Architecture
card	I-Architecture
.	O
</s>
<s>
They	O
do	O
not	O
require	O
a	O
separate	O
dongle	O
,	O
which	O
could	O
be	O
lost	O
or	O
misplaced	O
,	O
and	O
do	O
not	O
need	O
to	O
be	O
removed	O
from	O
the	O
laptop	B-Device
when	O
travelling	O
.	O
</s>
<s>
An	O
alternative	O
approach	O
is	O
to	O
use	O
larger	O
type	O
III	O
cards	O
with	O
a	O
regular	O
modular	B-Architecture
connector	I-Architecture
socket	O
,	O
but	O
this	O
approach	O
requires	O
more	O
space	O
.	O
</s>
<s>
Wi-Fi	O
PC	B-Architecture
cards	I-Architecture
for	O
accessing	O
wireless	O
networks	O
have	O
an	O
external	O
portion	O
containing	O
the	O
antenna	O
for	O
improved	O
reception	O
(	O
as	O
compared	O
with	O
inside	O
the	O
laptop	B-Device
)	O
,	O
but	O
this	O
portion	O
of	O
the	O
card	O
may	O
be	O
accidentally	O
damaged	O
while	O
moving	O
the	O
laptop	B-Device
.	O
</s>
<s>
3Com	O
manufactured	O
wireless	O
cards	O
with	O
retractable	O
antenna	O
portions	O
,	O
also	O
under	O
the	O
XJACK	B-Protocol
name	O
.	O
</s>
