iphone : How to keep 3G/GPRS preferred network in presence of Wifi?

Question

I am developing an application that communicates (UDP communication) with our server remotely through 3G/GPRS. As we have to establish serial communication with a digital device and our application through Wifi.

Now the problem is that when application connects with wifi it rejects 3G/GPRS and tries to find internet connectivity on wifi which it could not and as a result it lost connection with server.

Now I want to know that how can I keep my connection with 3G/GPRS and as well as with Wifi so that I could communication both with the server through internet (3G/GPRS) and with the device through wifi.

(Wifi does not have Internet at the moment as the application is using remotely in a Cab/Taxi)

Answer 1

If you don't specify a router when connecting to the Wifi of your device, the iPhone will use 3G for any non-local connections. If your device has a DHCP server, configure it to not specify a router.