I need to send commands to a device enabled with a GRPS connection from a server application. i.e think remote fare collection devices installed on trains/buses etc
the use case is an administrator using the server software to send a software update to the device or querying the remote device status.
my understanding is that GPRS enabled devices do not have static IP addresses. in this situation how does the communications happen, if the server needs to initiate the request?
i've heard about sending an SMS to the device like a wakeup call, so that in turn the GPRS device initiates a request to the server, but is this the only way?
Whether your devices have a static IP address depends on your service provider, I doubt many general GSM plans (the kind they sell to consumers) would offer static IPs for mobile devices. Service providers with special plans for special applications might offer them though, so it might be worth asking around.
You could make your thing work without the SMS by having your devices advertise their IP address when they connect to the network (just like dynamic DNS). However, if you're going to use a general service provider, you should make sure with them that they allow incoming traffic to devices - I've actually seen GSM service providers that simply don't allow any incoming traffic into GPRS devices, any port.