RLXIC-SV
♦
Intelligent Cellular
Data Communication and Host Modes
RadioLinx Intelligent Cellular Serial Modem for the Verizon Wireless CDMA Network
User Manual
Page 66 of 146
ProSoft Technology, Inc.
May 29, 2009
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 (that is, bound by the value S53 and/or AIP). Because 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 are not 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.
7.3.4 TCP and TCP Pad
When the RLXIC-SV is in a TCP session, all characters received on the serial
port are assembled into TCP packets, and sent to the mode'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
.
TCP auto answer is enabled (
S1
), a TCP connection request is received, and
the modem is not in a data session.
Data is received on the serial port, and
o
The Startup Mode Default (
MD
) is
4
(auto TCP)
o
The remote TCP destination, as defined in S53, successfully responds to
the TCP connection request.
The value of
S7
(TCP Connection Time-out) specifies the number of seconds to
wait, after initiating a TCP connection attempt, for a successful connection to be
established. If the connection has not been successfully established before the
time-out occurs, ERROR/BUSY is returned.
TCP packet assembly is affected by the values of
S50
(PAD Forwarding Time-
out) and
S51
(PAD Forwarding Character). Data received in the serial buffer will
be transmitted when the idle inter-character time-out specified in S50 (in tenths of
seconds) occurs or when a character is received that matches
S51
(if non-zero).
The TCP session will be terminated if no data is transmitted or received for the
time interval specified in
TCPT
and
TCPS
. TCPT is the number of minutes
(TCPS=0) or seconds (TCPS=1) used for this idle time-out.
Caution:
TCPT should never be 0 when using the TCP mode. A broken TCP session can result in
the modem being left with a TCP Auto Answer
