Developers guide

Chapter 22: Wireless Wide-Area Networking
Checking Packet Data Status
210 Psion Teklogix Mobile Devices SDK Developers Guide
22.6.4 Checking Packet Data Status
If packet data is enabled for the connection to the WWAN service provider, The WWAN driver
automatically configures the system so that a connection can be made using RAS or
Connection Manager.
The following example shows how to check the packet data status:
22.6.5 Roaming
Typically, in your home country the home network is selected automatically, and all other net-
works are forbidden. There is usually no national roaming.
If you are in another country, several networks may have roaming agreements with your home
network and you may want to manually select one—for example, the partner with the best tariff.
If the network is not selected manually, the WWAN modem automatically selects the network
with the highest signal strength.
If you are in a border area you can manually select your home network, in order to prevent
roaming to a partner network across the border with higher roaming charges.
Use SetRegisterState to manually select the a WWAN network. See “Access Flags” on page 212
for information on using the Set Register State Access Flag.
22.6.6 Connecting Manually to A WWAN Network
Usually, at startup the WWAN driver selects, connects to, and registers with, the appropriate net-
works for the SIM card.
If you call GetRegisterState and the return value indicates that the connection is deregistered,
then you must do one of the following to select the network:
•Use SetRegisterState, or
• Use the WWAN settings in the Wireless Manager Control Panel applet
See “The DbGprs.csv File” on page 209
for information that must be provided to the WWAN
network during connection.
Example 22.8 Checking Packet Service Status In C++
WWanRequestParameters opts;
opts.hWaitForAsyncCompletion = 0;
WWAN_PACKET_SERVICE packetService;
if (WirelessWAN::GetPacketService(opts, packetService) == WwanRequestSuccess)
{
if (packetService.AttachState == WwanAttachStateAttached)
{
// Packet data is now enabled. WWAN communication can start...
}
else if (packetService.AttachState == WwanAttachStateDetached)
{
// Packet data is NOT enabled, which means that either
// the service provider does not have packet data enabled,
// or the WWAN driver did not automatically select a network
// at startup, and it must be selected manually here.
}
}