RLXIC-EH
♦
Intelligent Cellular
Data Communication and Host Modes
RadioLinx Intelligent Cellular Ethernet Gateway for HSUPA (3G GSM) Networks
User Manual
Page 50 of 111
ProSoft Technology, Inc.
May 29, 2009
Using a private IP insulates the PPP client from changes in IP addresses of the
underlying network. The will perform basic NAT-like address translation on all
packets.
If a public IP address is being used, any changes in the IP (as determined by the
wireless network) will result in the PPP link to the host being disconnected,
requiring the host to reinitiate it. The public IP is passed to the host in the PPP
negotiations, so when the network forces a change, the modem has to force the
host to renegotiate the PPP link to make this happen.
7.3.2 SLIP
SLIP mode is entered be using the "
AT\ASLIP
" command. As in PPP Mode, the
IP address that the host assumes is affected by the setting of
*HOSTPRIVMODE. SLIP does not negotiate the IP address with the connected
device or computer, so before making a SLIP connection, the SLIP driver on that
device or computer must be configured to use the IP address specified by
querying
S110
.
When the modem is in UDP PAD (Packet Assembly and Disassembly) Mode,
all characters received on the serial port are assembled into UDP packets,
and sent to the remote IP address/port or the RLXIC-EH, and any packets
received from the same IP/port-destined for the device port of RLXIC-EH (see
*DPORT)--are disassembled, and dumped onto the serial line.
A UDP session is initiated by one of the following events:
Using the Dial UDP (DP) AT command (example, ATDP192.168.3.23/3456).
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).
Summary of Contents for RLXIC-EH
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