User's Manual Part 1

2 Product Overview — Introduction to GSM and GPRS
Revision 1.8 P/N 9002363
Introduction to GSM and GPRS
GPRS is a packet-switched technology, meaning that on a GPRS network, information is
split into separate but related packets before being transmitted and reassembled upon
receiving. The use of packets allows for greater transport flexibility, as the data is not tied
to one specific transport protocol (TCP, LAT,.25X and Telnet are examples of other
transport protocols).
As well as providing the user with design and development information, this chapter will
also provide the user with information on the following GPRS elements:
• network requirements
• local system requirements
• Interfaces
• hardware
•air
• electrical
• hardware (including pinout assignments)
• SIM card functions
GSM Technology
GSM uses a time division multiplexing access method that permits up to eight users to
communicate using one frequency channel. The channel is broken up into eight time slots
with each slot operating independently, sending data between the network and the mobile
device.
Figure 1 GSM–Merlin Interface