twinaxial cable
As early as the 1970s, a data cable with a twinaxial structure was used in terminal networks. This cable was called a twinaxial cable. With the increasing requirements for high-speed infrastructures such as High Performance Computing( HPC) and high-speed networks such as Gigabit Ethernet, 10 Gigabit Ethernet and 40 Gigabit Ethernet, new, high- performance twinaxial cables were developed whose properties are better than those of STP cables.
- The classic twinaxial cable is an IBM cable specially designed for IBM S/36, S/38 and AS/400 systems. It is a balanced cable with two inner conductors and a shield. This Twinax cable is available for indoor and outdoor installation. It is black, has a PVC jacket with a diameter of 8.25 mm and an impedance of 105 ohms. The attenuation values are 19.5 dB/100 m for frequencies up to 200 MHz.
- For high-speed networks such as Gigabit Ethernet( GbE), 10 Gigabit Ethernet, 40 Gigabit Ethernet, 100 Gigabit Ethernet, InfiniBand and Fibre Channel, Twinaxial cables have been developed as direct-connect cables for the highest data rates. In these direct-connect cables, which are used in data centers, several symmetrical wire pairs are individually shielded and provided with an overall shield. These are Balanced Shielded Cables. These twinaxial cables have very good shielding properties, offer the highest protection against electromagnetic interference( EMI) and the lowest propagation delay differences( skew). They are compact and are terminated at both ends with small transceiver modules, such as the SFP+ module the SFP+ module or the QSFP module. During high-precision prefabrication, various mechanical characteristics are optimized in terms of bandwidth and attenuation. These include the conductor material, the conductor thickness, the distance between the conductors and the diameter of the shielding. For 10GbE, 25GbE, 40GbE, 50GbE and 100GbE, the twinaxial cable is the IB4X cable for the 10GbE interface10GBase-CX4. An 8-pair twinaxial cable with a conductor cross-section of 28 AWG to 32 AWG. Data is transmitted via this twinaxial cable over four lanes each at a data rate of 3.125 Gbps. It is not only important that the individual Balanced Shielded Cables have low conductor resistances and low dielectric losses, but also as identical as possible properties in terms of insertion loss or latency.
