<s>
If	O
locally	O
powered	O
,	O
this	O
can	O
also	O
be	O
termed	O
an	O
active	B-Device
loudspeaker	I-Device
,	O
meaning	O
it	O
contains	O
an	O
audio	O
power	O
amplifier	O
that	O
drives	O
the	O
loudspeaker	O
.	O
</s>
<s>
A	O
network	B-Device
speaker	I-Device
implies	O
the	O
ability	O
to	O
send	O
audio	O
to	O
such	O
a	O
device	O
from	O
a	O
network	O
connection	O
,	O
usually	O
over	O
an	O
Ethernet	O
network	O
or	O
the	O
Internet	O
.	O
</s>
<s>
In	O
many	O
cases	O
this	O
type	O
of	O
speaker	O
also	O
contains	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
(	O
DSP	O
)	O
to	O
provide	O
the	O
audio	B-Algorithm
crossover	I-Algorithm
and	O
other	O
tonal	O
functions	O
that	O
exist	O
in	O
conventional	O
speakers	O
.	O
</s>
<s>
Network	B-Device
speakers	I-Device
are	O
also	O
known	O
as	O
IP	B-Device
speakers	I-Device
.	O
</s>
<s>
In	O
many	O
cases	O
the	O
IP	B-Device
speaker	I-Device
is	O
created	O
from	O
an	O
IP	O
audio	O
endpoint	O
—	O
a	O
device	O
with	O
the	O
requisite	O
network	O
connection	O
and	O
ability	O
to	O
process	O
audio	O
packets	O
,	O
but	O
without	O
the	O
actual	O
physical	O
speaker	O
portion	O
—	O
that	O
provides	O
amplified	O
audio	O
to	O
a	O
conventional	O
loudspeaker	O
or	O
unamplified	O
audio	O
(	O
i.e.	O
</s>
<s>
Subsequently	O
,	O
in	O
1988	O
,	O
Polle	O
T	O
.	O
Zellweger	O
,	O
Douglas	O
B	O
.	O
Terry	O
and	O
Daniel	O
C	O
.	O
Swinehart	O
of	O
Xerox	O
PARC	O
introduced	O
audio	B-Protocol
over	I-Protocol
Ethernet	I-Protocol
at	O
the	O
2nd	O
IEEE	O
Conference	O
in	O
a	O
paper	O
entitled	O
"	O
An	O
Overview	O
of	O
the	O
Etherphone	O
System	O
and	O
its	O
Applications	O
"	O
.	O
</s>
<s>
The	O
very	O
closely	O
related	O
technology	O
(	O
nearly	O
synonymous	O
)	O
,	O
Voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
,	O
which	O
generally	O
consists	O
at	O
a	O
minimum	O
of	O
a	O
microphone	O
on	O
one	O
end	O
,	O
a	O
speaker	O
on	O
the	O
other	O
end	O
,	O
with	O
a	O
network	O
connecting	O
them	O
;	O
began	O
widespread	O
use	O
in	O
1998	O
with	O
PCs	O
,	O
followed	O
shortly	O
after	O
by	O
dedicated	O
hardware	O
(	O
phones	O
with	O
built-in	O
VoIP	B-Application
capabilities	O
)	O
.	O
</s>
<s>
The	O
audio	O
content	O
played	O
by	O
the	O
processor	O
in	O
an	O
IP	B-Device
speaker	I-Device
is	O
communicated	O
from	O
its	O
source	O
across	O
a	O
packet-switched	B-Protocol
data	I-Protocol
network	I-Protocol
using	O
IPv4	B-Protocol
and	O
IPv6	B-Protocol
addressing	O
with	O
a	O
User	B-Protocol
Datagram	I-Protocol
Protocol	I-Protocol
(	O
UDP	O
)	O
or	O
Real-time	B-Protocol
Transport	I-Protocol
Protocol	I-Protocol
(	O
RTP	O
)	O
.	O
</s>
<s>
The	O
IP	B-Device
Speaker	I-Device
connects	O
to	O
Unicast	B-Protocol
or	O
Multicast	O
addresses	O
to	O
enable	O
the	O
delivery	O
of	O
streamed	O
data	O
from	O
a	O
source	O
on	O
the	O
network	O
,	O
to	O
arrive	O
at	O
a	O
single	O
speaker	O
or	O
many	O
speakers	O
respectively	O
.	O
</s>
