<s>
The	O
1100-series	O
IP	O
phones	O
are	O
6	O
different	O
desktop	O
IP	O
clients	O
manufactured	O
by	O
Avaya	O
for	O
Unified	O
communications	O
which	O
can	O
operate	O
on	O
the	O
SIP	B-Application
or	O
UNIStim	B-Protocol
protocols	O
.	O
</s>
<s>
The	O
SIP	B-Application
Firmware	O
supports	O
presence	O
selection	O
and	O
notification	O
along	O
with	O
secure	O
instant	O
messaging	O
.	O
</s>
<s>
As	O
such	O
it	O
began	O
as	O
a	O
UNIStim-only	O
phone	O
,	O
which	O
meant	O
that	O
the	O
phone	O
was	O
primarily	O
supported	O
with	O
only	O
Nortel	O
manufactured	O
voice	O
PBX	O
systems	O
.	O
</s>
<s>
In	O
2009	O
a	O
firmware	O
upgrade	O
was	O
made	O
available	O
to	O
allow	O
the	O
phone	O
to	O
function	O
on	O
the	O
SIP	B-Application
protocol	O
.	O
</s>
<s>
This	O
meant	O
that	O
the	O
phone	O
could	O
now	O
be	O
used	O
with	O
a	O
wide	O
variety	O
of	O
PBX	O
systems	O
including	O
those	O
produced	O
by	O
Nortel	O
,	O
Avaya	O
,	O
and	O
even	O
open-source	O
PBX	O
systems	O
such	O
as	O
Asterisk	B-Language
(	O
PBX	O
)	O
.	O
</s>
<s>
In	O
2010	O
a	O
VPN	B-Application
client	I-Application
was	O
added	O
to	O
the	O
firmware	O
as	O
of	O
release	O
0623C7F	O
.	O
</s>
<s>
This	O
means	O
that	O
it	O
is	O
very	O
easy	O
to	O
send	O
the	O
phone	O
to	O
a	O
remote	O
worker	O
location	O
with	O
a	O
typical	O
cable	O
modem	O
or	O
DSL	O
Internet	O
connection	O
and	O
the	O
phone	O
will	O
use	O
the	O
VPN	B-Application
capability	O
to	O
securely	O
establish	O
an	O
IP	O
tunnel	O
back	O
to	O
the	O
corporate	O
network	O
and	O
extend	O
a	O
standard	O
voice	O
telephone	O
extension	O
to	O
any	O
location	O
on	O
the	O
Internet	O
.	O
</s>
<s>
The	O
phone	O
can	O
support	O
up	O
to	O
sixteen	O
lines	O
through	O
the	O
UNIStim	B-Protocol
or	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	B-Application
)	O
protocols	O
.	O
</s>
