Specifications

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GPRS
GPRS is an extension of GSM network where packet switching data trafc is
supported. With GPRS each channel that is not busy with call trafc is available
for packet switching data trafc. Packets from several different users can be
mixed within the same channel, which results in efcient sharing of available
network resources.
GPRS permits even higher transfer rates as it uses several time slots for the
transfer. In theory rates of up to 115.2 kbit/s can be achieved, however, transfer
rates of between 20 – 50 kbit/s are more common. Transfer rate is however
dependent on several factors and some of them are: operator, terminal, number
of users on the same cell, distance to the base radio station (re-transmissions).
Establish a GPRS Connection
Communication with GPRS uses another procedure. GPRS is based on IP com-
munication and the connected unit must provide an IP address before a connec-
tion can be established.
This is done by:
… Connecting to the GPRS network.
… A dynamic address is assigned.
… The exchange of data can take place.
Not all operators can offer subscriptions with static address allocation. With
dynamic allocation, you do know from instance to instance which address has
been assigned to the opposing equipment. This is not a problem if the GPRS
modem initiate a connection to the master. The modem will get a dynamic IP-
address after a GPRS attached and can then connect to some equipment that
has a xed IP-address, for example, a computer.
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GPRS
GPRS attached
Dynamic IP addresses alloted
Transmitted/Received data
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GPRS
Internet
ISP
GPRS attached
Dynamic IP addresses alloted
Transmitted/Received data
AUDIN - 8, avenue de la malle - 51370 Saint Brice Courcelles
Tel : [phone] - Fax : [phone] - Web : http: www.audin.fr - Email : [e-mail]