<s>
A	O
standard	O
Swedish	O
telephone	B-Protocol
plug	I-Protocol
carries	O
one	O
telephone	O
line	O
and	O
has	O
four	O
flat	O
metal	O
pins	O
and	O
one	O
plastic	O
pin	O
.	O
</s>
<s>
The	O
design	O
is	O
only	O
used	O
in	O
Sweden	O
and	O
older	O
installations	O
in	O
Iceland	O
(	O
RJ11	O
and	O
a	O
data/voice	O
standard	O
using	O
an	O
8P8C	O
modular	B-Architecture
connector	I-Architecture
are	O
used	O
in	O
more	O
recent	O
buildings	O
)	O
.	O
</s>
<s>
Neither	O
plug	O
nor	O
socket	O
is	O
compatible	O
with	O
other	O
plugs	B-Architecture
and	O
sockets	O
.	O
</s>
<s>
It	O
is	O
defined	O
in	O
Swedish	O
Standard	O
SS	B-Protocol
455	I-Protocol
15	I-Protocol
50	I-Protocol
.	O
</s>
<s>
When	O
a	O
subscriber	O
has	O
more	O
than	O
one	O
telephone	B-Protocol
socket	I-Protocol
,	O
they	O
typically	O
are	O
connected	O
so	O
that	O
two	O
telephones	O
can	O
not	O
be	O
connected	O
to	O
the	O
telephone	O
exchange	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
When	O
all	O
sockets	O
on	O
a	O
line	O
are	O
connected	O
in	O
parallel	O
only	O
the	O
lower	O
pins	O
on	O
a	O
Swedish	O
Standard	O
plug	O
(	O
middle	O
connectors	O
on	O
RJ-plugs	O
)	O
are	O
used	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
standard	O
Swedish	O
plugs	B-Architecture
and	O
sockets	O
,	O
RJ11	O
connectors	O
are	O
quite	O
common	O
,	O
especially	O
in	O
offices	O
.	O
</s>
<s>
Even	O
8P8C	O
modular	B-Architecture
telephone	I-Architecture
sockets	I-Architecture
can	O
be	O
found	O
.	O
</s>
<s>
Most	O
telephone	O
equipment	O
sold	O
in	O
Sweden	O
today	O
has	O
RJ11	O
sockets	O
and	O
corresponding	O
cables	O
with	O
6P4C	O
plugs	B-Architecture
on	O
each	O
end	O
and	O
an	O
adaptor	O
from	O
RJ11	O
to	O
SS	B-Protocol
455	I-Protocol
15	I-Protocol
50	I-Protocol
sockets	O
.	O
</s>
<s>
The	O
Swedish	O
practice	O
with	O
sockets	O
connected	O
in	O
cascade	O
can	O
be	O
maintained	O
with	O
RJ	O
plugs	B-Architecture
and	O
sockets	O
by	O
using	O
the	O
first	O
pair	O
for	O
connecting	O
the	O
terminal	O
equipment	O
to	O
the	O
PSTN	O
and	O
the	O
second	O
pair	O
for	O
the	O
connection	O
of	O
a	O
line	O
towards	O
the	O
next	O
socket	O
.	O
</s>
<s>
6P6C	O
modular	B-Architecture
plugs	I-Architecture
are	O
also	O
used	O
for	O
telephony	O
,	O
but	O
only	O
for	O
certain	O
telephone	O
exchange	O
systems	O
-	O
never	O
for	O
direct	O
connection	O
to	O
the	O
PSTN	O
.	O
</s>
<s>
ISDN	B-Protocol
telephones	O
and	O
outlets	O
always	O
have	O
8P8C	O
modular	B-Architecture
connectors	I-Architecture
.	O
</s>
