<s>
Network	B-Protocol
Termination	I-Protocol
1	I-Protocol
(	O
NT1	O
)	O
or	O
Network	O
Termination	O
type	O
1	O
refers	O
to	O
equipment	O
in	O
an	O
Integrated	B-Protocol
Services	I-Protocol
Digital	I-Protocol
Network	I-Protocol
(	O
ISDN	B-Protocol
)	O
that	O
physically	O
and	O
electrically	O
terminates	O
the	O
network	O
at	O
the	O
customer	O
's	O
premises	O
.	O
</s>
<s>
The	O
NT1	O
network	O
termination	O
provides	O
signal	O
conversion	O
and	O
timing	O
functions	O
which	O
correspond	O
to	O
layer	B-Application
1	I-Application
of	O
the	O
OSI	O
model	O
.	O
</s>
<s>
In	O
a	O
Basic	B-Protocol
Rate	I-Protocol
Interface	I-Protocol
,	O
the	O
NT1	O
connects	O
to	O
line	O
termination	O
(	O
LT	O
)	O
equipment	O
in	O
the	O
provider	O
's	O
telephone	O
exchange	O
via	O
the	O
local	B-Architecture
loop	I-Architecture
two	O
wire	O
U	B-Protocol
interface	I-Protocol
and	O
to	O
customer	O
equipment	O
via	O
the	O
four	O
wire	O
S	B-Protocol
interface	I-Protocol
or	O
T	B-Protocol
interface	I-Protocol
.	O
</s>
<s>
The	O
S	O
and	O
T	B-Protocol
interfaces	I-Protocol
are	O
electrically	O
equivalent	O
,	O
and	O
the	O
customer	O
equipment	O
port	O
of	O
a	O
NT1	O
is	O
often	O
labelled	O
as	O
S/T	O
interface	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
the	O
U	B-Protocol
interface	I-Protocol
is	O
the	O
termination	O
point	O
of	O
the	O
ISDN	B-Protocol
network	O
.	O
</s>
<s>
In	O
Europe	O
,	O
the	O
NT1	O
is	O
generally	O
provided	O
by	O
the	O
provider	O
,	O
and	O
the	O
S/T	O
is	O
the	O
termination	O
point	O
of	O
the	O
ISDN	B-Protocol
network	O
.	O
</s>
