User's Manual

Getting Started
Singal strength affecting cellular transmissions
You need to be in an area that is covered by a GPRS/GSM network
to use the GlobeTrotter card.
Cellular networks differ from landline networks in many ways.
For example, traffic loads and the strength of radio singals may
vary in a cellular network and cause handovers.
It is recommended that you move the card to a location where
the strongest possible cellular signal can be obtained. When the
signal is strong, cellular transmission is the most efficient.