Trimble Inc. TRIMTRAC1 Benutzerhandbuch
DRAFT TrimTrac Locator Technical Manual 9
The GSM system is made up of two sections:
•
The Base Station Subsystem that controls the radio link with the mobiles
through local cells
through local cells
•
The Network Subsystem that controls the switching of calls between the
network users, mobile to mobile, and between mobile and fixed lines
network users, mobile to mobile, and between mobile and fixed lines
The Network Subsystem stores all administrative information including the
current cell being used by the mobile unit that allows call routing and the roaming
ability of GSM. An important feature of GSM is this ability to move across
international and network borders, a feature that is described as “roaming.” If
arrangements have been made with the service provider, the SIM card will be
enabled for roaming.
current cell being used by the mobile unit that allows call routing and the roaming
ability of GSM. An important feature of GSM is this ability to move across
international and network borders, a feature that is described as “roaming.” If
arrangements have been made with the service provider, the SIM card will be
enabled for roaming.
•
Mobile Station (MS)
o
The TrimTrac locator includes a radio transmitter and receiver.
o
Subscriber Identity Module (SIM) – an electronic card containing a
computer chip. The chip contains the subscriber information and
operating system parameters. SIMs provide authentication,
encryption, information storage, and subscriber account protection
services (including Personal Identity Number or PIN, and Pin
Unblocking Key or PUK). GSM users can move the SIM from one
TrimTrac locator to another.
computer chip. The chip contains the subscriber information and
operating system parameters. SIMs provide authentication,
encryption, information storage, and subscriber account protection
services (including Personal Identity Number or PIN, and Pin
Unblocking Key or PUK). GSM users can move the SIM from one
TrimTrac locator to another.
•
Other network components (part of the GSM network)
o
Short Message Service Center (SMSC)
o
Delivers text messages (up to 160 characters) to GSM users.
GSM Operational Overview
The TrimTrac locator operates in accordance with the state diagram more fully
described the Operation chapter beginning on page 24 of this manual.
described the Operation chapter beginning on page 24 of this manual.
Whenever the TrimTrac locator has a new position or status to report, it updates
its Status Message. The TrimTrac locator then enters the GSM Transmit State
and automatically searches for a GSM network using a set of tables on the SIM
card to determine which GSM network the phone should try to reach.
its Status Message. The TrimTrac locator then enters the GSM Transmit State
and automatically searches for a GSM network using a set of tables on the SIM
card to determine which GSM network the phone should try to reach.