Stavo studiando il manuale del protocollo Easy GPRS dei modem integrati Telit e guarda un po' che esempio mi trovo a pagina 8
1.1.1 CSD application example

Let’s suppose you have several remote meteorological measurement units spread around the territory,
and you want to access them wirelessly through a GSM module in CSD operation.
For each remote unit, there's a modem to connect with the server application, with its own SIM card
and unique phone number.
Com'è piccolo il mondo