1000BaseCX or 1000Base-CX

is a physical layer specification for Gigabit Ethernet transmission over a special balanced 150 ohm cable shorter than 25m. This cable is a type of shielded cable. In order to minimize safety and interference concerns caused by voltage difference, both transmitters and receivers will share a common ground. The return loss for each connector is limited to 20db to minimize transmission distortions. The connector type for 1000Base-CX will be a DB-9 connector or HSSDC. IEEE Specification: IEEE 802.3z