Most of new brand of Samsung (SGH-I900, SGH-Z400, SGH-U700 and more), cannot originate call nor receive call if they are served by Siemens BSC.
Location Update, SMS, GPRS are working correctly.
On Outgoing call, the MSC doesn’t receive the setup message and the call setup is dropped on a timer expiry
On Terminating call, the mobile rings but cannot connect.
If possible give me your mail adress then I can send to you the conclusion from MSC vendor.