The SPX connector is a proprietary Ethernet and PoE connector developed by Starlink. It is a 9-pin connector that has 8 pins mapped to the eight wires used by Ethernet. The additional pin is a shield/shell ground wire.
Found on the Enterprise Dish V4 power-supply cable (Dish ↔ PSU). The cable ships with a 9-pin SPX at the PSU end and a waterproof RJ-45 at the Dish end.
There’s also a beefier “HP SPX” variant (still 9-pin) on the High-Performance Enterprise terminal’s PSU for higher current.