Transition
Networks
E
‐
100BTX
‐
FX
‐
06
User
Guide
33791
Rev.
A
http://www.transition.com/
Page
7
of
13
Active
Link
Pass
‐
Through
(ALPT)
Link
Pass
‐
Through
is
a
troubleshooting
feature
that
allows
the
media
converter
to
monitor
both
the
fiber
and
copper
RX
ports
for
loss
of
signal.
With
the
loss
of
RX
signal
on
one
media
port,
the
converter
will
automatically
disable
the
TX
signal
of
the
other
media
port,
thus
“passing
through”
the
link
loss.
End
device
automatically
notified
of
link
loss
Prevents
loss
of
valuable
data
unknowingly
transmitted
over
invalid
link
Active
LPT
is
a
form
of
LPT
that
requires
the
links
to
become
Active
before
LPT
becomes
Active.
With
Active
LPT
there
are
2
states:
Diagnostic
and
Active
.
The
media
converter
enters
the
Diagnostic
state
when
either
of
the
following
conditions
is
met:
Upon
power
‐
up
of
the
converter.
Upon
losing
Link
on
either
the
copper
or
fiber
ports.
In
the
Diagnostic
state,
the
link
for
each
of
the
media
converter’s
ports
can
come
up
independently
of
each
other,
just
like
a
converter
that
has
no
LPT
functionality,
or
a
converter
that
has
LPT
is
disabled.
The
Diagnostic
state
is
helpful
during
first
power
up,
before
all
links
of
a
circuit
are
connected,
as
it
allows
the
installer
to
see
each
link
turn
on
as
the
cables
are
plugged
in.
It’s
also
helpful
for
finding
the
location
of
a
fault,
if
one
exists.
The
media
converter
remains
in
the
Diagnostic
state
until
the
following
condition
is
met:
The
link
status
for
both
of
the
media
converter’s
ports
is
up,
simultaneously.
After
that
condition
is
met,
ALPT
enters
the
Active
state.
It
remains
in
the
Active
state
until
the
converter
is
either
powered
down,
or
either
the
copper
port
or
the
fiber
port
loses
Link.
In
the
Active
state,
Active
LPT
works
as
shown
below
(the
same
as
when
regular
LPT
is
enabled).