With 2050 v1/v2, according to the licence terms when you installed it, you were supposed to have purchased a CD for every copy. That is why Nortel/Avaya only offers the full ISO on a CD. With 2050 v3/v4, you no longer have to purchase a CD for every copy but do need to purchase a separate RTU for every copy. In all cases above (either with CD or RTU), this is in addition to the keycode applied to the BCM.