Developers guide

Chapter 22: Wireless Wide-Area Networking
Selecting An Access Point Name (APN)
Psion Teklogix Mobile Devices SDK Developers Guide 211
22.6.7 Selecting An Access Point Name (APN)
An Access Point Name (APN) identifies an external network that is accessible from a
Psion Teklogix computer. An APN has several associated attributes that define how the computer
can access the external network at that point.
In most cellular networks there are two types of APNs:
• Wireless Application Protocol (WAP) APN, enabling access to the default WAP content (or
the network operator's walled garden). This APN normally filters non-WAP content by traffic,
ports, or volume.
• Internet or WEB APN, which enables access to all Internet content.This APN is normally
unfiltered and often the network operator charges a higher tariff for it. This connection is
needed when using applications or an HTML browser.
By default, the user interface (WWANUI) sets up the correct packet data context., including the
Internet APN. You may want to configure more APNs, if you have arranged with your service pro-
vider to use more than one SIM card, or to grant your SIM card access to several APNs. Use
SetProvisionedContexts to make these APN changes.
User name, password, and authentication method have to be set through RAS; however, to be
compatible with possible future SDK changes, applications should fill in AuthenticationType,
UserName, and Password when calling SetProvisionedContexts.
22.6.8 Connecting To A VPN
A VPN (Virtual Private Network) can be used to connect a WWAN modem to a corporate net-
work. Some third-party VPN clients work correctly only in conjunction with the Microsoft
ASYNCMAC driver. In the standard Mobile Devices SDK implementation of WWAN,
ASYNCMAC is not used. Psion Teklogix proprietary modules complete the communication
between NDIS and the WWAN modem.
When using a third-party VPN client, in the Wireless Manager applet WWAN configuration
screen, select Use virtual serial port. This gives access to ASYNCMAC through the virtual serial
port. This is shown in the following diagram:
The virtual serial port cannot be enabled from within the Mobile Devices SDK.
NDIS
ASYNCMAC
TAPI
Unimodem
WWAN driver Virtual serial port
Serial driver
WWAN modem
NDIS
ASYNCMAC
TAPI
Unimodem
WWAN driver Virtual serial port
Serial driver
WWAN modem