If i try to make call using more than one mobile simultaneously to the same network, i am not able to do so. Can the network handle more than one call simultaneously?
There is probably some bug in the network because of which you faced this problem. Generally networks should be able to handle many calls simultaneously. There are some testing devices that allow the network to test this feature as well. Aeroflex TM500 for instance allows upto 32 UE's to simultaneous make calls on a network.
If i try to make a call from Mobile A to mobile B and at the same time from Mobile B to Mobile A, none of them rings. I get busy tone on both the phones, why?
When you initiate a call on a mobile, they stop monitoring the paging channel. So if a Paging is sent to the mobile they wont receive it. Hence this behaviour is correct. You will not receive a ringtone on either mobile.