The PBX in the telephone lines, Urban, of all communication, by the call center management. In fact, the call center that specifies any number, what is linear is related to, or any person what amount of contact. In VOIP systems, the Management number by the PBX are done.PBX, the server that the task of making calls, internal and external (lines, VOIP lines, Urban), they are responsible. In fact, whenever you number, enter this number to the PBX has gone and the PBX decides that you have with respect to the number entered to which one of the lines connected), or which audio file for you to run. Due to all this description can be received that the PBX, the most important components in the VOIP network.