User guide

Raven EDGE/GPRS for Cingular - User Guide, version 2.31 20
CHAPTER 5 Data Communication and Host Modes
The Raven plays the part of a HOST when a computer or another device is connected to its serial
port. The Raven can also route data to/from the connected device to the cellular
network.
Note: The Raven moves data from one port to the cellular network in a simple one-
to-one routing. It does not employ a routing table or any complicated routing pro-
to
col. If you need to have one-to-many routing, you can connect the Raven to a
router. The router would provide the multiple routing and the Raven would pro-
vide one-to-one for the router to the cellu
lar net
work and the Internet.
As the host, the Raven can use different communication modes.
AT: The Raven accepts and resp
onds to
standard AT commands.
PassThru: Direct conn
ection to internal hardware (OEM Module) of the Raven.
Telnet: The Raven auto-an
swers TCP connections to allow terminal emulation using the cellular
connection.
PPP: The Raven uses PPP to communicate with a device or
computer connected to the serial port.
SLIP: The Raven uses SLIP to communicate with a devi
ce or computer connected to the serial
port.
UDP and UD
P P
AD: Any data received on the serial port is assembled into UDP packets and sent
to the session’s associated IP address and Port (described later). Any responses received from the
associated IP address and port destined for the modem's Device Port are unwrapped and sent out
the serial port.
TCP and TCP P
A
D: Any data received on the serial port is packaged into TCP messages and
sent to the associated connection’s IP address and Port (described later). Any data received from
the TCP peer is unwrapped and sent out the serial port.
By default, the Raven is in AT Mode and allows AT Commands to be entered via terminal con-
nection (through the local port connection) or rem
o
tely (through the cellular network). PassThru
Mode can only be exited by resetting the Raven. All other modes are entered by use of a startup
mode command.