Technical data

www.westermo.com Theoretical and general applications 93
Differences between GSM and GPRS
Applications with GSM and GPRS
The possibility to utilise GSM and GPRS in data communication is an alternative to
radio communication. Wireless applications are primarily used for communication
where there are no leased lines or network connections. Nevertheless, communica-
tion using a GSM or GPRS modem
requires certain basic conditions.
The GSM modem connects to the
GSM network. A connection is made
through the MSC and BSC and out
on a PSTN line to the computer. As the
GSM connection is made through a circuit switched
network you are constantly connected until the line
is disconnected.
CSD
Circuit Switched Data
TDM
Time Division Multiplexing
One timeslot is used which gives
a maximum throughput of 14.4 kbit/s.
The running cost is based on how long the
connection is made regardless of the
amount of data sent.
By using four timeslots and Coding
Scheme 4 the maximum throughput
will be 85,6 kbit/s.
The running cost is based on the
amount of data sent (number of packets)
regardless of connection time.
GPRS
General Packet Radio Service
TDM
Time Division Multiplexing
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MSC
BSC BST
GSM
PSTN
Telephone
004614112233
ATD
004614112233
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