18
Fig. 10
GPRS connection via VPN tunnel
TM
04 71
29 151
0
PC Tool, etc.
SCADA system
Clients
LAN
GRE router
GRE router
VPN tunnel
Internet
GSM operator
GSM/GPRS
network
Base station
APN
CIU 250 with
CIM 250 module
and SIM card
Mobile phone
"Static"
IP address
Setup, status and
control commands
via SMS