Data Communication and Host Modes
Rev 3.0B Feb.08
54
until
it
receives
an
acknowledgement
with
this
sequence
number.
If
an
acknowledgement
is
not
received
within
the
time
‐
out
period
(specified
in
S7),
the
data
will
be
retrans
‐
mitted.
This
will
continue
until
an
acknowledgement
is
received
or
the
modem
is
reset.
Likewise
any
UDP
packets
received
by
the
Raven
are
expected
to
have
this
simple
header.
The
Raven
will
issue
an
acknowledgement
for
any
valid
packets
which
are
received.
To
configure
the
Raven
for
a
normal
UDP
session,
you
need
to
set
the
Startup
Mode
Default
to
73
(ATMD73).
If
you
are
using
two
modems,
configure
the
Destination
IP
and
Port
in
each
to
point
to
each
other.
Serial
data
will
then
be
sent
reliably
between
the
two.
Caution: Although it adds reliability, the simple implementation of the
Reliable UDP mode in the does not check for duplicate packets.
UDP Multicast Mode
UDP
Multicast
mode
results
in
any
data
received
from
the
host
serial
port
being
sent
to
all
the
clients
in
the
address
list.
The
remote
port
number
is
taken
from
S53.
To
avoid
flooding
the
network,
the
packets
are
sent
to
each
client
with
a
20ms
pause
in
between.
The
receipt
of
UDP
packets
works
as
in
normal
UDP
mode
(i.e.
bound
by
the
value
S53
and/or
AIP).
Since
it
may
take
a
while
to
transmit
the
data
to
all
hosts
(especially
if
all
20
Modbus
entries
are
used
and
name
resolutions
are
required),
new
data
received
from
the
host
port
is
buffered
until
current
transmissions
to
all
hosts
are
finished.
Enter
the
list
of
target
IPs
in
the
address
list
(ADDR
LIST).
The
index
numbers
in
the
list
aren
ʹ
t
used.
Configure
for
a
normal
UDP
session.
Set
the
Startup
Mode
Default
to
83
(ATMD83).
Configure
the
Destination
port
to
match
the
device
port
of
the
remote
modems.
TCP and TCP Pad
When
the
Raven
is
in
a
TCP
session,
all
characters
received
on
the
serial
port
are
assembled
into
TCP
packets
and
sent
to
the
mode
ʹ
s
remote
IP
address/port,
and
any
packets
received
from
the
remote
end
of
the
TCP
connection
are
disassembled
and
dumped
onto
the
serial
line.
A
TCP
connection
is
established
by
one
of
the
following
methods:
•
Using
the
Dial
TCP
(DT)
AT
command.
For
example,
ATDT192.168.3.23/3456
.
