Matrix DFE-Gold Series PoE Module Hardware Installation Guide C-1
C
About PoE (Power over Ethernet)
This
appendix
provides
an
overview
of
Power
over
Ethernet
Technology
and
how
it
is
implemented
in
relation
to
the
4H4285
‐
49.
Overview
Power
over
Ethernet
(PoE)
refers
to
the
ability
to
provide
operational
power
to
a
device
connected
to
a
data
network
using
the
same
cabling
that
provides
the
data
interface.
Modern
Ethernet
implementations
employ
differential
signals
over
twisted
pair
cables.
This
requires
at
a
minimum
of
two
twisted
pairs
for
a
single
physical
link.
Both
ends
of
the
cable
are
isolated
with
transformers
blocking
any
DC
or
common
mode
voltage
on
the
signal
pair.
PoE
exploits
this
fact
by
using
two
twisted
pairs
as
the
two
conductors
to
supply
a
direct
current.
One
pair
carries
the
power
supply
current
and
the
other
pair
provides
a
path
for
the
return
current.
While
several
proprietary
legacy
implementations
of
PoE
have
been
deployed
by
LAN
equipment
vendors,
in
2003
the
IEEE
published
the
IEEE
802.3af
‐
2003
specification,
which
is
part
of
the
802.3
suite
of
standards.
The
4H4285
‐
49
is
fully
compliant
with
the
IEEE
802.3af
standard.
It
supports
the
standard
resistor
based
detection
method,
as
well
as
AC
disconnect
capability.
The
4H4285
‐
49
is
also
capable
of
supplying
the
maximum
specified
current
to
all
ports
simultaneously.
Each
PD
has
a
PDC
(Powered
Device
Classification)
that
is
transmitted
to
the
DFE module
for
power
management
purposes.
Table C
‐
1
on
page C
‐
1
lists
the
classifications
and
the
associated
power
ranges.
Table C-1 Powered Device Classifications
Class
Usage
PD Maximum Power Range Usage
0
Default
0.44 to 12.95 Watts
1
Optional
0.44 to 3.84 Watts
2
Optional
3.84 to 6.49 Watts
3
Optional
6.49 to 12.95 Watts
4
Not Allowed
Reserved for Future Use
Summary of Contents for 6H308-48
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Page 56: ...Completing the Installation 3 28 Installation...
Page 70: ...Regulatory Compliance A 4 Specifications...
Page 88: ...PoE Port Status LEDs C 4 About PoE Power over Ethernet...
