Technical data

www.westermo.com Theoretical and general applications 95
There are solutions to this problem, but connected applications must sup-
port this. One example is to send the assigned IP address to the opposite
side via SMS.
You must be aware that if any of the con-
nected devices is subjected to a power fail-
ure the procedure must be repeated as it
would have lost its IP address.
The problem occurs when a unit, for example, a computer wants to communicate
with peripheral equipment and the computer generates the connection. No one
knows the IP address that the computer
should connect to, as these are assigned
dynamically.
Another application where the same type of problem occurs is when two devices
need to communicate and none of them is the master. The modem can not initiate IP
communication as it does not know which
address will be assigned.
GPRS
Internet
ISP
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GPRS
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GPRS
GPRS attached
Dynamic IP addresses alloted
Transmitted/Received data
GPRS connection
B A C K