[bedoig]

It was actually a setting that allowed voice calls to interrupt an active EVDO connection. Being one of the first EVDO devices, not all the kinks were quite worked out when it launched. One of the bugs being that voice calls (1x) would simply be ignored if EVDO was active. The entry allowed calls to "ring-through" (pause) an EVDO connection. Search for "ring-through hack" and I bet you find some results.