Cisco AGS+, Hardware Installation And Maintenance

Page: 68 / 146

Configuring
Cards
Most
DTE
interfaces require
Normal
External Transmit Clock
signal All
DCE
interfaces
require
an
Internal
Transmit
Clock noninverted
signal
The
MCI
card clocking
options
are
controlled
by
jumper areas
W40
through
W53
and
the
SCI
card clocking options
are
controlled
by jumper areas
Nil
through
N28
Occasionally
delays occur
between
the
Serial
Clock
Transmit External
SCTE
clock
and
the
transmitted data
that
may
push
the data
transition out
to
the point
where
using an inverted
clock
is
appropriate jumpers
W42
aiid
W52
for the
MCI
and
N13 N17 N23
and
N27
for
the
SCI
however
an inverted clock
is
not
recommended
Typical
delays indicate
that
the inverted clock
may be appropriate
above
1.3
megabits per
second
Mbps
depending upon
the
DTE
clock-to-data
skews
and
setup required
and
allowing
some margin
for
temperature cable
and
other variables
Some
DCE
devices
will not accept
SCTE
so Serial
Clock
transmit
CT
must
be
used
Inverting
the clock may be the only
way to
compensate
for the cable length
and
circuit delays in the
DTE
and
DCE
Table 5-5
and
Table
5-6
show
the
jumper
settings
for the
MCI
and
SCI
clock
options respectively
The
last
two columns
of these
tables
DTE
and
DCE
indicate the
setting
that
should be
used
with
either
DTE
or
DCE
applique
Unless
specifically
noted
all products
are shipped with the factory
default
setting
to
work
with the
DTE
applique
which
requires external clocking the
channel service
unit/digital
service unit
CSU/DSU
provides the
clocking
for the circuit
Table
5-5
CSC-MCI
Jumper
Settings
for
Clock Options
Jumper Pair
Signal Description
Interface
DIE DCE
W53
Normal
External
Transmit Clock
Serial
X1
W52
Inverted External
Transmit Clock
Serial
W5
Normal
Internal
Transmit Clock
Serial
W50
Inverted Internal
Transmit Clock
Serial
W43
Normal
External
Transmit Clock
Serial
X1
W42
Inverted External
Transmit Clock
Serial
W41
Normal
Internal Transmit Clock
Serial
W40
Inverted Internal
Transmit Clock
Serial
Recommended
setting
Available but not
recommended
Maintenance
5-11