Service manual

II-D.
System
Wiring
Both
physical
and
electrical
considera-
results
in
a
loss
of
sidetone
null
at
tions
are
involved
in
determining
the
remote
stations,
some
level
loss
from
best
system
wiring
configuration.
The
remote
stations
to
the
main
station,
physical
aspects
center
around
ease
of
reduced
headset/speaker
output
before
wiring,
whereas
the
electrical
aspects
clipping,
and,
in
the
ground
conductor,
are
dictated
by
performance
requirements
a
serious
increase
in
crosstalk.
of
the
entire
system
and/or
particular
stations
in
the
system.
The
two
main
Build-up
of
capacitance
results
in
re-
electrical
considerations
for
the
cable
duced
sidetone
null
at
all
stations
on
are
resistance
in
the
conductors
and
the
line(s)
in
question,
and
reduced
capacitance
between
the
conductors.
voice
clarity
due
to
excessive
high-
frequency
roll-off.
Build-up
of
resistance
in
the
cable
There
are
three
main
methods
of
configuring
your
system
wiring
(ANY
combination
of
them
can
be
used
in
one
system):
l
8
Bt EEl
Daisy-Chain
1.
This
daisy-chain
method
requires
the
least
amount
of
cable,
but
may
be
impractical
because
of
your
facility's
physical
layout.
Also,
if
a
e
break
occurs
in
cabling,
all
stations
beyond
the
break
are
disabled
(this
problem
is
solved
by
the
loop-through
shown
in
Method
2):
Loop-Through
2.
Method
2
provides
another
advantage
in
that
the
DC
resistance
accu-
mulated
in
the
cable
is
no
more
than
half
as
great
as
in
the
standard
daisy-chain
arrangement.
However,
it
also
results
In
a
cumulative
cable
capacitance
which
may
be
twice
as
great
as
Method
l's.
"Hub"
3.
This
"hub"
method
is
especially
useful
for
belt-packs
and
situations
in
which
running
two
cables
to
the
remote
stations
is
cumbersome.
The
hub
method
usually
results
in
fairly
low
cable
resistance
between
stations,
but
cumulative
capacitance
is
often
the
highest
of
the
three
methods.
8