What is twinaxial cable (twinax)?
A twinaxial cable (twinax) is a type of cable that is similar to the usual coaxial copper cable, but has two inner conductors instead of one. It was mainly used by IBM for its IBM3x and AS / 400 computer systems. The cable has recently become particularly popular for applications requiring high speed differential signaling in a short range such as B. in local networks, further used.
Twinaxial cables were originally made for IBM computer hardware such as the IBM 5250, IBM printers and their midrange hosts, and iSeries systems running IBM i5 / OS. It was designed by IBM to be high speed (1Mbps) and can have multiple addressable devices per connection; Seven devices can be addressed from workstation addresses 0 to 6. The main disadvantage of this initially was the large connectors that usually required screws to stay in place.
The twin conductors of the twinax cable do not carry individual signals, nor are one viewed as data and the other as ground. The cable works in half-duplex mode because both connections have to transmit data. For example, to return a 0, wire A must be greater than wire B for the first half of the bit duration, and then A must be less than B for the next half. To return a 1, the opposite is done. All of this happens in 250 ns.