Shielded patch cable with dual-layer jacket aims for 10-Gig systems
Feb. 15, 2006 - Despite the shielding, the cable terminates to unshielded modular plugs with standard dimensions.
Quabbin Wire & Cable Co. (www.quabbin.com) recently introduced the DataMax 10 Gig patch cable, intended for use in unshielded twisted-pair cabling systems that will support 10GBase-T. The cable has 100-ohm impedance, is shielded, and has a dual-layer jacket. It does not use an internal spline or have oversized copper conductors, its manufacturer says, making them easy to terminate using high-performance unshielded modular plugs with standard dimensions.
During the termination process, an appropriate length of the jacket is cut away, which also removes the shielding tape between the jackets. The inner jacket and insulated conductors are then prepared and terminated as required by the plug being used. The outer jacket is usually covered by a strain-relief boot or shrink-tube.
The DataMax 10Gig patch cable has excellent resistance to power-sum alien crosstalk, Quabbin says, with more than 10-dB margin over the TIA/EIA-568B.2-10 (Augmented Category 6) proposed minimums. Testing the cable using TIA's proposed 6-around-1 congifuation produces low measured values-close to the floor of a network analyzer, the manufacturer reports. This performance assures reliable 10GBase-T transmission for Category 6 channels, Quabbin also says.
In a statement announcing the patch cable, Quabbin spelled out the critical role that patch cable, and patch cords, play in successful 10GBase-T transmission. Its statement read in part: "PSAXT is the total interference transmitted from the pairs in adjacent cables into the pairs of the victim cable. Since this noise is not a signal generated by the victim, transceiver cancellation circuitry cannot be 'trained' to cancel it out from the intended data stream. Because 10GBase-T Ethernet protocol is signaling at high data rates and low signal levels, it is particularly susceptible to very low noise levels. Alien crosstalk noise levels are inherently low and subject to attenuation as they propagate toward the 10GBase-T transceivers at the channel ends. Thus, PSAXT is predominantly a channel-end effect. Since patch cords are usually installed at both ends of a channel, successful transmission of 10 Gigabit Ethernet most often depends on patch cable PSAXT performance. Cords made with DataMax 10Gig cable provide the needed performance headroom for Category 6A channels."