What’s twinax?Twinaxial cabling, or "Twinax", is a type of cable similar to coaxial cable, but with two inner conductors instead of one. Due to cost efficiency it is becoming common in modern very-short-range high-speed differential signaling applications.
Applications(应用)：SFP+ Direct Attach (10GSFP+Cu)This is a copper 10 Gigabit Ethernet cable that comes in either an active or passive twin-ax cable assembly and connects directly into an SFP+ housing. The active twin-ax cable has active electronic components in the SFP+ housing to improve the signal quality; the passive twin-ax cable is just a straight “wire” and contains no active components. Generally twin-ax cables that are less than 5 meters in length are passive and greater than 5 meters in length are active but this is a general rule of thumb and will vary from vendor to vendor. SFP+ Direct Attach is expected to be the optimum solution for reaches of 10 m.
One of major applications includes Arista Networks and Cisco Systems implementation coupled with SFP+ modules. This type of connection is able to transmit at 10 Gigabit full duplex speed over 5 meter distances. Moreover this setup offers 15 to 25 times lower transceiver latency than current 10GBASE-T CAT6/CAT6a/CAT7 cabling systems: 0.1 μs for Twinax with SFP+ versus 1.5 to 2.5 μs for current 10GBASE-T specification. The power draw of Twinax with SFP+ is around 0.1 watts, which is also much better than 4–8 watts for 10GBASE-T.
As always with cabling one of the consideration points is Bit error ratio or BER for short. Twinax copper cabling has BER better than 10−18 according to Cisco, and therefore is acceptable for applications in critical environments.
This SFP+/Twinax is also referred to as 10GBASE-CR by some manufacturers, even though there is no IEEE or other standard with that name
SATA-3 CablesSome SATA-3 cables are implemented using twin-ax.
DisplayPortMany manufacturers of DisplayPort cabling are also using twinaxial configurations to accommodate the strict insertion loss, return loss, and crosstalk requirements for the 2.7 Gbit/s signaling rate.