This read-write string specifies the SVC address used to forward a busy hunt group B call over an ACT SDM-FP switched virtual circuit, and per the MIB's note it is only honored when sysHuntForwardingBUnit is left empty. An administrator uses this field to route hunt group B's overflow calls over an on-demand SVC path instead of a named unit forwarding target. For example, an admin wanting group B's busy calls to use a switched circuit rather than a fixed unit destination would clear sysHuntForwardingBUnit and populate this SVC address instead.