<s>
Com21	B-Device
was	O
an	O
early	O
pioneer	O
in	O
developing	O
cable	B-Device
modem	I-Device
networks	O
in	O
the	O
era	O
before	O
the	O
standard	O
DOCSIS	B-Protocol
was	O
introduced	O
for	O
Internet	O
access	O
via	O
cable	O
television	O
networks	O
.	O
</s>
<s>
Com21	B-Device
Inc	O
.	O
was	O
an	O
American	O
public	O
company	O
.	O
</s>
<s>
Com21	B-Device
shares	O
traded	O
on	O
Nasdaq	O
using	O
CMTO	O
as	O
symbol	O
.	O
</s>
<s>
Com21	B-Device
had	O
offices	O
in	O
13	O
countries	O
.	O
</s>
<s>
Com21	B-Device
was	O
quite	O
successful	O
with	O
their	O
cable	B-Device
modem	I-Device
line	O
of	O
products	O
in	O
the	O
years	O
before	O
the	O
new	O
standard	O
DOCSIS	B-Protocol
was	O
available	O
.	O
</s>
<s>
The	O
Com21	B-Device
portfolio	O
can	O
be	O
divided	O
into	O
three	O
segments	O
:	O
the	O
central	O
or	O
head	O
end	O
equipment	O
,	O
cable	B-Device
modems	I-Device
or	O
CPE	O
,	O
and	O
the	O
management	O
platform	O
.	O
</s>
<s>
The	O
central	O
system	O
,	O
typically	O
installed	O
in	O
the	O
head	O
end	O
or	O
CATV	B-Protocol
hub	O
locations	O
were	O
called	O
ComControllers	O
.	O
</s>
<s>
A	O
ComController	O
provided	O
the	O
same	O
function	O
as	O
a	O
CMTS	B-Device
in	O
modern	O
Docsis	B-Protocol
networks	O
.	O
</s>
<s>
A	O
ComcCntroller	O
was	O
a	O
19	O
"	O
rack	O
module	O
that	O
was	O
built	O
around	O
an	O
integrated	O
ATM	O
switch	O
and	O
needed	O
several	O
modules	O
to	O
become	O
a	O
functional	O
cable	B-Device
modem	I-Device
head	O
end	O
system	O
.	O
</s>
<s>
The	O
management	O
module	O
provided	O
the	O
interface	O
between	O
each	O
ComController	O
system	O
and	O
the	O
Com21	B-Device
network	O
management	O
platform	O
NMAPS	O
.	O
</s>
<s>
The	O
downstream	O
controller	O
had	O
two	O
F-connector	O
interfaces	O
to	O
connect	O
a	O
coax	O
cable	O
towards	O
the	O
distribution	O
section	O
of	O
a	O
hybrid	B-Architecture
fibre	I-Architecture
coax	I-Architecture
cable	O
TV	O
network	O
.	O
</s>
<s>
Each	O
upstream	O
receiver	O
module	O
offered	O
two	O
interfaces	O
towards	O
the	O
HFC	B-Architecture
network	I-Architecture
.	O
</s>
<s>
To	O
connect	O
the	O
cable	B-Device
modem	I-Device
network	O
to	O
the	O
Internet	O
,	O
a	O
ComController	O
had	O
one	O
or	O
more	O
network	O
modules	O
.	O
</s>
<s>
In	O
the	O
early	O
models	O
of	O
the	O
ComControllers	O
,	O
network	O
modules	O
offered	O
two	O
10BASE-T	B-Protocol
interfaces	O
.	O
</s>
<s>
Each	O
of	O
these	O
Ethernet	O
interfaces	O
could	O
be	O
linked	O
to	O
a	O
VLAN	B-General_Concept
within	O
the	O
Com21	B-Device
network	O
.	O
</s>
<s>
The	O
first	O
successor	O
was	O
a	O
network	O
module	O
with	O
a	O
fast	B-Protocol
Ethernet	I-Protocol
(	O
100	O
Mbit/s	O
)	O
interface	O
,	O
but	O
this	O
interface	O
lacked	O
the	O
option	O
of	O
VLANs	B-General_Concept
.	O
</s>
<s>
As	O
VLAN	B-General_Concept
support	O
was	O
really	O
needed	O
to	O
offer	O
reliable	O
services	O
to	O
the	O
users	O
of	O
a	O
cable	B-Device
modem	I-Device
network	O
,	O
the	O
next	O
version	O
of	O
the	O
network	O
controller	O
was	O
a	O
single	O
ATM	O
interface	O
offering	O
an	O
OC3	O
or	O
STM-1	B-Protocol
-	O
155	O
Mbit/s	O
optical	O
interface	O
.	O
</s>
<s>
Com21	B-Device
named	O
their	O
cable	B-Device
modems	I-Device
ComPort	O
.	O
</s>
<s>
Over	O
the	O
years	O
,	O
Com21	B-Device
offered	O
several	O
models	O
of	O
their	O
cable	B-Device
modems	I-Device
.	O
</s>
<s>
The	O
idea	O
of	O
this	O
module	O
slot	O
was	O
that	O
a	O
cable	B-Device
modem	I-Device
network	O
would	O
also	O
offer	O
a	O
telephone	O
service	O
.	O
</s>
<s>
Via	O
a	O
special	O
connector	O
a	O
systems-engineer	O
could	O
connect	O
this	O
interface	O
to	O
the	O
serial	O
communications	O
(	O
RS-232	O
)	O
port	O
of	O
a	O
PC	O
to	O
monitor	O
the	O
activity	O
of	O
a	O
cable	B-Device
modem	I-Device
.	O
</s>
<s>
Com21	B-Device
developed	O
early	O
DOCSIS	B-Protocol
cable	I-Protocol
modems	I-Protocol
,	O
obtaining	O
DOCSIS	B-Protocol
1.1	O
certification	O
on	O
Broadcom	O
3350	O
(	O
DOXPort	O
1110	O
)	O
and	O
3345	O
(	O
DOXPort	O
1110XB	O
)	O
designs	O
.	O
</s>
<s>
Com21	B-Device
also	O
made	O
a	O
CMTS	B-Device
called	O
the	O
DOXcontroller	O
1000XB	O
,	O
which	O
was	O
OEMed	O
by	O
ARRIS	O
(	O
as	O
the	O
Cadant	O
C3	O
)	O
.	O
</s>
<s>
Upon	O
Com21	B-Device
's	O
Chapter	O
7	O
bankruptcy	O
,	O
it	O
was	O
purchased	O
by	O
ARRIS	O
,	O
and	O
was	O
later	O
DOCSIS	B-Protocol
2.0	O
certified	O
.	O
</s>
<s>
To	O
manage	O
a	O
network	O
with	O
one	O
or	O
more	O
ComControllers	O
and	O
all	O
connected	O
cable	B-Device
modems	I-Device
,	O
Com21	B-Device
offered	O
their	O
network	O
management	O
platform	O
,	O
called	O
NMAPS	O
.	O
</s>
<s>
NMAPS	O
was	O
a	O
proprietary	O
platform	O
using	O
the	O
HP	B-Application
OpenView	I-Application
platform	O
.	O
</s>
<s>
A	O
typical	O
feature	O
of	O
a	O
Com21	B-Device
network	O
was	O
that	O
the	O
cable	B-Device
modems	I-Device
did	O
n't	O
get	O
an	O
IP	O
address	O
.	O
</s>
<s>
ComControllers	O
were	O
configured	O
via	O
NMAPS	O
:	O
setting	O
the	O
frequencies	O
for	O
the	O
downstream	O
and	O
upstream	O
signals	O
,	O
define	O
VLANs	B-General_Concept
and	O
enabling	O
the	O
cable	B-Device
modems	I-Device
in	O
one	O
of	O
the	O
created	O
VLANs	B-General_Concept
.	O
</s>
<s>
Before	O
the	O
worldwide	O
acceptance	O
of	O
the	O
DOCSIS	B-Protocol
standard	O
,	O
Com21	B-Device
was	O
highly	O
successful	O
in	O
the	O
industry	O
.	O
</s>
<s>
By	O
2000	O
,	O
Com21	B-Device
had	O
shipped	O
over	O
500,000	O
modems	O
and	O
1,000	O
ComControllers	O
.	O
</s>
<s>
The	O
networks	O
using	O
the	O
Com21	B-Device
system	O
passed	O
15	O
million	O
households	O
worldwide	O
.	O
</s>
<s>
On	O
July	O
15	O
,	O
2003	O
,	O
Com21	B-Device
went	O
out	O
of	O
business	O
.	O
</s>
<s>
The	O
company	O
filed	O
for	O
Chapter	O
11	O
bankruptcy	O
and	O
its	O
DOCSIS	B-Protocol
cable	I-Protocol
modem	I-Protocol
assets	O
were	O
sold	O
to	O
ARRIS	O
.	O
</s>
