<s>
Pbxnsip	B-Protocol
is	O
a	O
software	O
implementation	O
of	O
a	O
telephone	O
private	B-Device
branch	I-Device
exchange	I-Device
(	O
PBX	B-Device
)	O
produced	O
by	O
a	O
company	O
of	O
the	O
same	O
name	O
.	O
</s>
<s>
Like	O
any	O
PBX	B-Device
,	O
it	O
allows	O
attached	O
telephones	O
to	O
make	O
calls	O
to	O
one	O
another	O
,	O
and	O
to	O
connect	O
to	O
other	O
telephone	O
services	O
including	O
the	O
public	O
switched	O
telephone	O
network	O
(	O
PSTN	O
)	O
and	O
Voice	B-Application
over	I-Application
Internet	I-Application
Protocol	I-Application
(	O
VoIP	B-Application
)	O
services	O
.	O
</s>
<s>
Its	O
name	O
is	O
a	O
combination	O
of	O
the	O
acronyms	O
PBX	B-Device
and	O
SIP	B-Application
(	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
)	O
.	O
</s>
<s>
Pbxnsip	B-Protocol
is	O
released	O
under	O
a	O
proprietary	B-Application
license	I-Application
with	O
trial	O
versions	O
available	O
on	O
the	O
pbxnsip	B-Protocol
website	O
.	O
</s>
<s>
Pbxnsip	B-Protocol
was	O
acquired	O
on	O
October	O
4	O
,	O
2010	O
by	O
IP	O
Phone	O
maker	O
Snom	O
.	O
</s>
<s>
In	O
order	O
to	O
focus	O
on	O
the	O
VoIP	B-Application
handset	O
business	O
in	O
2012	O
,	O
the	O
IP-PBX	O
product	O
line	O
of	O
Snom	O
technology	O
was	O
spun	O
out	O
into	O
Vodia	O
Networks	O
.	O
</s>
<s>
The	O
name	O
pbxnsip	B-Protocol
was	O
dropped	O
in	O
favor	O
of	O
the	O
name	O
"	O
Vodia	O
"	O
which	O
is	O
easier	O
to	O
pronounce	O
.	O
</s>
<s>
Originally	O
designed	O
for	O
Linux	B-Application
,	O
pbxnsip	B-Protocol
now	O
also	O
runs	O
on	O
a	O
variety	O
of	O
different	O
operating	B-General_Concept
systems	I-General_Concept
including	O
Microsoft	B-Application
Windows	I-Application
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
Pbxnsip	B-Protocol
software	O
includes	O
many	O
features	O
available	O
in	O
traditional	O
PBX	B-Device
systems	O
:	O
voice	O
mail	O
,	O
conference	O
calling	O
,	O
interactive	O
voice	O
response	O
(	O
phone	O
menus	O
)	O
,	O
and	O
automatic	O
call	O
distribution	O
.	O
</s>
<s>
To	O
attach	O
traditional	O
analogue	O
telephones	O
to	O
a	O
pbxnsip	B-Protocol
installation	O
,	O
or	O
to	O
connect	O
to	O
PSTN	O
trunk	O
lines	O
,	O
requires	O
the	O
use	O
of	O
a	O
SIP	B-Application
adapter	O
.	O
</s>
<s>
A	O
number	O
of	O
firms	O
sell	O
PCI	B-Protocol
cards	I-Protocol
to	O
attach	O
telephones	O
,	O
telephone	O
lines	O
,	O
T1	O
and	O
E1	O
lines	O
,	O
and	O
other	O
analog	O
and	O
digital	B-Application
phone	I-Application
services	O
to	O
a	O
system	O
.	O
</s>
<s>
Alternatively	O
,	O
a	O
user	O
can	O
use	O
SIP	B-Application
phones	O
and	O
a	O
SIP	B-Application
carrier	O
and	O
use	O
a	O
data	B-Architecture
network	I-Architecture
to	O
handle	O
all	O
hardware	O
aspects	O
of	O
connecting	O
telephones	O
.	O
</s>
<s>
Pbxnsip	B-Protocol
can	O
inter-operate	O
with	O
most	O
SIP	B-Application
telephones	O
,	O
acting	O
both	O
as	O
registrar	O
and	O
as	O
a	O
gateway	O
between	O
IP	O
phones	O
and	O
the	O
PSTN	O
.	O
</s>
<s>
Pbxnsip	B-Protocol
supports	O
only	O
the	O
SIP	B-Application
protocol	O
(	O
see	O
Comparison	O
of	O
VoIP	B-Application
software	O
for	O
examples	O
)	O
.	O
</s>
<s>
By	O
supporting	O
a	O
mix	O
of	O
traditional	O
and	O
VoIP	B-Application
telephony	I-Application
services	O
,	O
pbxnsip	B-Protocol
allows	O
deployers	O
to	O
build	O
new	O
telephone	O
systems	O
,	O
or	O
gradually	O
migrate	O
existing	O
systems	O
to	O
new	O
technologies	O
.	O
</s>
<s>
Some	O
sites	O
are	O
using	O
pbxnsip	B-Protocol
servers	O
to	O
replace	O
proprietary	B-Application
PBXes	O
;	O
others	O
to	O
provide	O
additional	O
features	O
(	O
such	O
as	O
voice	O
mail	O
or	O
voice	O
response	O
menus	O
,	O
or	O
virtual	O
call	O
shops	O
)	O
or	O
to	O
reduce	O
costs	O
by	O
carrying	O
long-distance	O
calls	O
over	O
the	O
Internet	O
(	O
toll	O
bypass	O
)	O
.	O
</s>
<s>
VoIP	B-Protocol
telephone	I-Protocol
companies	I-Protocol
can	O
,	O
as	O
an	O
option	O
,	O
support	O
pbxnsip	B-Protocol
as	O
a	O
user	O
agent	O
or	O
trunked	O
connection	O
with	O
SIP	B-Protocol
trunking	I-Protocol
protocols	O
along	O
with	O
ATAs	O
and	O
other	O
software	O
user	O
agents	O
.	O
</s>
<s>
VoIP	B-Protocol
telephone	I-Protocol
companies	I-Protocol
can	O
also	O
support	O
multiple	O
instances	O
of	O
pbxnsip	B-Protocol
in	O
a	O
multi-tenant	O
mode	O
allowing	O
them	O
to	O
offer	O
Cloud	O
based	O
or	O
"	O
hosted	O
"	O
solutions	O
to	O
businesses	O
.	O
</s>
<s>
The	O
PBX	B-Device
has	O
a	O
special	O
focus	O
on	O
security	O
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
first	O
SIP	B-Application
PBX	B-Device
systems	O
that	O
supported	O
the	O
Secure	B-Protocol
Real-time	I-Protocol
Transport	I-Protocol
Protocol	I-Protocol
and	O
seems	O
to	O
be	O
robust	O
against	O
forms	O
of	O
Denial	O
of	O
Service	O
,	O
for	O
example	O
the	O
INVITE	O
of	O
Death	O
.	O
</s>
<s>
There	O
is	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
(	O
GUI	B-Application
)	O
for	O
pbxnsip	B-Protocol
which	O
allows	O
administrators	O
to	O
view	O
,	O
edit	O
,	O
and	O
change	O
various	O
aspects	O
of	O
pbxnsip	B-Protocol
via	O
a	O
web	O
interface	O
.	O
</s>
<s>
While	O
initially	O
developed	O
in	O
the	O
United	O
States	O
,	O
pbxnsip	B-Protocol
has	O
become	O
a	O
popular	O
VOIP	B-Application
PBX	B-Device
worldwide	O
due	O
to	O
its	O
design	O
,	O
extensibility	O
,	O
and	O
excellent	O
feature	O
set	O
.	O
</s>
