Sierra Wireless EV-DO - Manual (Page 69)

Data Communication and Host Modes
Rev 3.0B Feb.08 64
meantime) 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
retransmitted. This will continue until an acknowledgement is
received or the modem is reset. Likewise any UDP packets
received by the PinPoint‐E are expected to have this simple
header. The PinPoint‐E will issue an acknowledgement for any
valid packets which are received.
To configure the PinPoint‐E 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 arenʹt 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 PinPoint‐E is in a TCP session, all characters
received on the serial port are assembled into TCP packets and
sent to the modeʹs remote IP address/port, and any packets
received from the remote end of the TCP connection are disas‐
sembled 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.