This read-only object is the integer index uniquely identifying this Pulse Per Second port within its card, part of a 16-port PPS group distinct from the earlier per-port f3PulsePerSecondPort table. Admins and management tools use it to address a specific PPS port among the sixteen grouped together on this card. For example, a monitoring tool uses pps16PortGroupIndex to identify exactly which of the sixteen PPS ports on a densely packed timing card reported a signal loss.