User manual

RLXIC-SG ♦ Intelligent Cellular Data Communication and Host Modes
RadioLinx Intelligent Cellular Serial Modem for Global GPRS/GSM User Manual
Page 56 of 136 ProSoft Technology, Inc.
May 29, 2009
In response to any of the preceding commands, the RLXIC-SG will respond with
CONNECT a carriage return and new line and is ready for the host to begin PPP
negotiations. The IP received by the host in the resulting negotiation will either be
a private (non-routable) IP address or a public (network-routable) IP address
provided by the network, depending on the settings of *HOSTPRIVMODE. If
*HOSTPRIVMODE=1, the value of the private IP address can be determined
beforehand by querying S110. The private IP address to be used can be defined
with the command AT*HOSTPRIVIP=192.168.100.33, substituting the desired IP
address.
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.