How will NSURLConnection respond if a connection is left open (i.e. Comet) and a phone call/SMS arrives on a CDMA network?

Question

If my application uses NSURLConnection to keep a connection open (to implement server push) on a CDMA network, then what will happen if the user makes a phone call or receives an SMS etc. (i.e. where simultaneous data and voice connections are not possible). Presumably didFailWithError will get called but I'm specifically wondering if its possible to determine the specific cause for the failure being these scenarios.