Sierra Wireless 20070914 - Manual (Page 80)

Data Communication and Host Modes
Rev 3.0B Feb.08 67
• Setting the Startup Mode Default (MD) to 3 (UDP) so that
a UDP session is entered automatically when the modem
registers onto the network. Serial data will be sent to the
IP/port specified in S53.
Incoming UDP packets will be processed out the serial port if
• UDP auto answer is enabled (S82=2);
• The destination IP address matches that in S53 (if Friends
Mode is enabled, the IP address also needs to be present
on the Friends List);
• Or allow any IP is set (AIP=1);
• The modem is in AT mode (not in a current UDP or TCP
session).
UDP 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).
UDP Auto Answer
UDP auto answer (previously called UDP half‐open) is set
with S82=2. When set, the PinPoint X will automatically
establish a UDP session to the source IP address and port of
the UDP packet received. The PinPoint X will remain “locked”
to this one remote IP/port until no data is sent or received for
the time interval defined in the UDP auto answer time‐out
(S83). During this session, packets from other IP/port
addresses will be rejected, unless *UALL is set. Whether or not
an incoming packet will cause the modem to enter a UDP
session is always dependent on the S53 and AIP settings.
The Normal UDP Mode (MD3) can be combined with UDP
auto answer to cause the incoming serial data to be sent in
UDP packets (instead of being treated as AT commands), while
allowing sessions to be established from different UDP
sources. A UDP session will be initiated either by incoming
serial data or by an incoming UDP packet. The session, started
by either method, will be terminated when no data has been
sent or received for the S82 period. Once the session termi‐
nates, another may be initiated by either means.
When idle, after the time‐out has occurred, the modem is in AT
command mode on the serial port, and any valid AT command
may be entered during this time.