As further to ISDNmans reply.
TCP does NOT mean they are received in an orderly fashion, it means they are all received. As it's voice, theirs no point waiting for a missed packet if it's going to delay the whole conversation. You'd suffer serious jitter. UDP is much, much faster, therefore much better suited to the job.
Stu..
Only the truly stupid believe they know everything.
Stu.. 2004