incoming call problem

Hi,

I work on Nokia 3250 (without UMTS). My application download some data 
from internet. At the same time i try to call (from different phone) to 
my phone but nothing appear.
It's is posible to have gprs (EDGE) connection and voice connection at 
the same time ?

How can I detect incomming calls and, eventually, puse my current data 
connetion ?

thanks in advance