This is the outgoing-call counterpart to ccasRSTIncomingRegSigDuration, setting the overall time budget for register signaling to complete once the gateway sends its first forward register signal. Having separate incoming/outgoing overall-duration timers lets an admin tune tolerance differently depending on call direction, which matters because outgoing calls depend on a remote exchange's responsiveness that the admin's own network does not control as tightly as it controls incoming-side behavior. An admin might set this to a longer value than the incoming variant if outgoing calls routinely traverse a slower or higher-latency carrier network for register signaling.