Motorola SYMBOL MINISCAN MSXX04 Guía de usuario descargar pdf (Pagina 218)

Chapter 19: Wireless Wide-Area Networking

Connecting to the Internet

Psion Mobile Devices Developers Guide

206

19.7 Connecting to the Internet

A WWAN modem must initiate a connection. This behaviour is similar to a dial-up connection but different

from an Ethernet interface which connects automatically. When a WWAN modem is attached to a network

and powered up, it detects the network, but is unable to transfer packets to the network until a packet data

connection is set up.

Figure 19.1 Interaction Between Mobile Devices SDK WWAN And Windows Components

The WWAN functions in the Mobile Devices SDK provide extra features that are needed by a WWAN connec-

tion, but not by an Ethernet or dial-up connection. These features include the ability to:

• Query the radio signal strength

• Select one of several available networks

The Wireless Manager applet in the GUI allows you to configure settings for the WWAN connection. This

gives access to many of the WWAN driver functions, without the necessity of writing code. This includes

activities such as querying the signal strength. The Wireless Manager applet uses RAS to connect and

disconnect WWAN connections.

19.7.1 Windows Embedded CE 5.0, Windows Embedded CE 6.0, Windows Mobile 2003 SE,

and Windows CE .NET 4.2

The following provide the RAS (Remote Access Service) API for making Internet connections.

• Windows Embedded CE 5.0

• Windows Embedded CE 6.0

An application can use the Windows RAS API to set up and tear down a WWAN connection.

NDIS

WWAN NDIS-WAN

Miniport driver

Virtual serial port

Serial driver

WWAN modem

PPP

TCP/UDP

Winsock API

Packets

RAS

RAS API

NdisUio2

WWAN API

WWAN Control Panel

user interface