MVME333P
and
MVME334AP Cabling
MVME333P
and
MVME334AP Cabling
The EIA-530 Serial Interface
Module
(SIM) for
the
MVME333P
and
MVME334AP
provides
a
true
EIA-530 interface, or
with
an
adapter
to a
37-position D-shell connector, a
true
V.36 interface. All
the
interface signals are
V.ll
(EIA-422)
balanced
lines
with
the exception of the
RL,
LL,
and
TM signals
which
(per the EIA-530
and
V.36 specification) are V.lO (EIA-423)
single-ended
signals.
The
EIA-530 DB-25 connector
cannot
be
directly connected to
the
DB-25
connector of
the
MVME705
or
MVME709 series of transition modules. The
MVME705/709 series
have
a "V.35/V.36 Interface" option,
but
this is
not
compatible
with
the EIA-530 interface for
two
reasons.
The
first incompatibility is
in
the
pinout
of
the
connector.
The
signals
on
the
DB-25 connector for
the
MVME705
/709
are
not
on
the
same
pins
as
the
signals
on
the EIA-530 DB-25 connector.
Even
if
this is resolved
by
using
an
adaptor
cable, a second level of incompatibility exists.
This second incompatibility is
due
to
the
nature
of the V.28 (EIA-232) receivers
used
on
the
MVME705
/709
transition
boards.
These receivers
have
an
extremely
wide
hysteresis
band
for
maximum
noise immunity. This
has
the
disadvantage
of
requiring
the
input
to
be
below
-2.0 VDC before
the
receiver
will detect
it
as a
low
(negated)
input.
The
V.ll
(EIA-422) drivers
on
the
EIA-530 SIM only
drive
low
to
about
+0.5 VDC. Some V.28 receivers
would
reliably detect this as a
low
(negated)
input,
however,
the
receivers
on
the
MVME705/709 transition
boards
do
not.
If
you
wish
to connect
the
MVME333P
and
MVME334AP to the MVME705
or
MVME709 transition
boards,
the
preferred
method
is to configure
both
ports
as
V.28 (EIA-232).
If
this is
not
possible, configure the MVME333P
or
MVME334AP
as
EIA-530,
and
the
MVME705/709 as a "V.35/V.36 Interface,"
and
only connect
the
data
and
clock lines
using
the
next table.
Since the
modem
control (handshake) lines are
not
connected,
in-band
flow
control
(XON
/XOFF
protocol)
must
be
used. This
assumes
that
one
port
is
configured as DTE,
and
the
other
port
is configured
as
DCE.
S900RF/D4
B-7
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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