User's Guide

Draft 1 BlueTree Wireless BT-4600/BT-5600 Product Manual 11
Router mode: In router mode, the modem establishes a PPP Client
connection with the network on the WAN side while a PPP Server
accepts connections on the LAN side over the serial port. Packets are
routed between the two connections for proper forwarding.
Note: Ethernet and future USB LAN-side connections automatically
assume a router mode.
Simple Modem mode: In Simple Modem mode, there are no PPP
negotiations established by the modem. The modem simply operates
at the physical layer and the PPP negotiations are passed-through
between the LAN and WAN sides.
The next sections assume host connections over the serial port.
Modem configured to start in Always-On mode
The modem can be configured to start in Always On mode. The
modem configuration is accomplished using AT commands from a
connection terminal like Microsoft® HyperTerminal, or using BlueTree
Device Manager. Upon modem startup, this mode causes the modem
to automatically establish and maintain a PPP connection with the
network on the WAN side.
This connection requires a connection profile to be configured in the
modem prior to connecting.
Note: In this mode, the modem can achieve autonomous
communication, like reporting GPS data to preconfigured IP
destinations, without the need for a host.
When a host, attached to the serial port of a modem in the Always-On
mode, sends a dial command to the modem, the following connection
behavior applies:
• If the dial string is the special string “#BTPPPS” or is the same dial
string used in the modem connection profile of the modem, router
mode comes in effect, PPP server is started and accepts the
connection.
• If the dial string is not “#BTPPPS” and is different from the one
used in the configured connection profile, then the WAN-side
connection is terminated and the modem reverts to the Simple
Modem mode as described above.
Modem configured to start in On-Demand mode
In this mode, the same logic applies as in the Always-On mode with
the exception that the WAN connection is established only when a dial
command is received from the LAN-side.
If no connection profile is configured in the modem, the On-Demand
connection always puts the modem in Simple Modem mode except
when the “#BTPPPS” dial string is used. In this case, PPP server starts
on the LAN side and a PPP connection is established with the modem
only.