Airlink EDGE/GPRS - Manual (Page 31)

PinPoint-E EDGE/GPRS - User Guide, version 2.32 25
Data Communication and Host Modes
FIGURE 5. Wireless Ace: PPP/Ethernet
Using a private IP insulates the PPP client from changes in IP addresses of the underlying net-
work. 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.
Slip Mode
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 with the host, so before making a SLIP connection, the host SLIP driver must be configured to
use the IP specified by querying S110.
UDP Pad
When the modem is in UDP PAD (Packet Assembly and Disassembly) Mode, all characters
received on the seial port are assembled into UDP packets and sent to the PinPoint-E’s remote IP
address/port, and any packets received from the same IP/port-destined for the PinPoint-E’s device
port (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 automati-
cally when the modem registers onto the network. Serial data will be sent to the IP/port speci-
fied in S53.