<s>
This	O
list	B-Protocol
of	I-Protocol
SIP	I-Protocol
software	I-Protocol
documents	O
notable	O
software	B-Application
applications	I-Application
which	O
use	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	O
)	O
as	O
a	O
voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
protocol	O
.	O
</s>
<s>
CommuniGate	B-Protocol
Pro	I-Protocol
,	O
virtualized	O
PBX	O
for	O
IP	O
Centrex	O
hosting	O
,	O
voicemail	O
services	O
,	O
self-care	O
,	O
...	O
</s>
<s>
Dialexia	O
VoIP	B-Application
Softswitches	O
,	O
IP	O
PBX	O
for	O
medium	O
and	O
enterprise	O
organizations	O
,	O
billing	O
servers	O
.	O
</s>
<s>
Speedflow	O
Communications	O
VoIP	B-Application
class	O
4/5	O
softswitches	O
with	O
integrated	O
billing	O
,	O
transcoding	O
,	O
SIP-H.323	O
converter	O
.	O
</s>
<s>
Voice	B-Application
Elements	I-Application
Inventive	O
Labs	O
 '	O
.NET	O
Voice	O
Development	O
software	O
and	O
SIP	O
stack	O
platform	O
.	O
</s>
<s>
Librestream	B-Application
's	O
2500	O
Camera	O
,	O
5000HD	O
camera	O
,	O
Onsight	O
Cube	O
(	O
wearable/modular	O
camera	O
)	O
,	O
Onsight	O
Connect	O
(	O
Windows	B-Application
,	O
iOS	B-Protocol
,	O
Android	O
)	O
.	O
</s>
<s>
Polycom	O
PVX	O
,	O
for	O
Windows	B-Application
.	O
</s>
<s>
Empathy	B-Language
,	O
using	O
GTK	B-Application
libraries	O
and	O
Telepathy	B-Protocol
framework	O
,	O
GPL	B-License
,	O
discontinued	O
in	O
earliest	O
visible	O
,	O
2021	O
.	O
</s>
<s>
pfSense	B-Protocol
,	O
a	O
firewall/router	O
distribution	O
based	O
on	O
FreeBSD	B-Operating_System
and	O
PF	B-Protocol
;	O
has	O
QoS	O
that	O
properly	O
tags	O
VoIP	B-Application
traffic	O
and	O
a	O
SIP	O
proxy	O
package	O
that	O
is	O
available	O
for	O
NATed	O
endpoints	O
.	O
</s>
<s>
Its	O
functionality	O
can	O
be	O
expanded	O
with	O
packages	O
like	O
FreeSWITCH	B-Language
,	O
a	O
free/open	O
source	O
software	O
communications	O
platform	O
for	O
making	O
SIP	O
,	O
voice	O
and	O
chat	O
driven	O
products	O
.	O
</s>
