Попробуйте это.
-(void) makeCall{
NSString* phoneNumber=yourTextFiled.text;//TextFiled
NSString *phoneNumber = [NSString stringWithFormat:@"%@",phoneNumber];
NSURL* callUrl=[NSURL URLWithString:[NSString stringWithFormat:@"tel:%@",phoneNumber];
//check Call Function available only in iphone
if([[UIApplication sharedApplication] canOpenURL:callUrl]){
[[UIApplication sharedApplication] openURL:callUrl]];
}
else{
UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"ALERT" message:@"This function is only available on the iPhone" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
[alert release];
}
}
Надеюсь, это действительно поможет вам.