Three High-Speed Copper Solutions
With the development of fiber optic technology, the copper wire technology shows some shortcomings, such as low bandwidth, short transmission distance, and poor durability and security, etc. While the combination of transceiver module and copper cabling can not only push the limits of copper, but also make it a good solution for short range applications. Typically there are three copper solutions for high performance network communications platforms: copper transceivers, loopbacks and DACs (direct attach cables).
Copper Transceivers
There are many optical transceivers that can achieve data transfer rates rivaling fiber-optic speeds while utilizing existing copper infrastructure and switch equipment, such as SFP (Small Form-factor Pluggable). 1000BASE-T copper SFP transceiver is based on the SFP Multi Source Agreement (MSA). It is compatible with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 802.3z and 802.3ab. 1000BASE-T SFP transceiver can plug into standard SFP interface allowing for 1000Base-T Gigabit transmission over standard Category 5 twisted pair copper for links of up to 100 meters. This innovative copper SFP module solution provides a simple and cost-effective option for Gigabit Ethernet applications. The following picture shows a 1000Base-T SFP copper transceiver.
Loopbacks
Loopbacks can be used in both copper and optical ports. Generally, there are QSFP+, CXP, SFP, SFP+, and XFP copper loopbacks for testing and diagnostics with high speed networks and system protocols. They are specifically designed to support copper implementation of Fiber Channel and other serial data applications which require extremely high data transfer rates over long distances. They can provide up to 12 pairs of transmit data channels connected to the corresponding receive channels. Some loopbacks, such as QSFP+ form can offer a cost effective alternative to test with optical links.
Direct Attach Cables
DAC is a form of high-speed cable with transceivers on either end used to connect switches to routers or servers. Seeing from the material of the cable, DAC can be classified into direct attach copper cable and active optical cable (AOC). Direct attach copper cables can either be passive or active, while AOC cables are always active. Today’s direct attach copper cable can support higher data rates than traditional copper interfaces—from 10Gbps to 40Gbps and even 100Gbps per channel. Direct attach copper cable is designed to use the same port as an optical transceiver, but compared with optical transceivers, the connector modules attached to the cable leave out the expensive optical lasers and other electronic components, thus achieving significant cost savings and power savings in short reach applications.
Direct attach copper cables are commonly used in 10G and 40G networks. For 10G networks, SFP+ direct attach copper cable, or 10g copper SFP, with SFP+ connector modules permanently attached to each end of the cable, can transmit and receive 10Gbps data through one paired transmitters and receivers over a thin twinax cable. It provides high performance in 10 Gigabit Ethernet network applications. For 40G networks, QSFP+ to QSFP+ copper cables and QSFP+ to 4 x SFP+ copper cables are widely applied. These cables are compliant with SFF-8431 and SFF-8436 specifications. QSFP+ to 4 x SFP+ copper cables provide connectivity between devices using QSFP+ port on one end and multiple SFP+ ports on the other end. They can fill the expanding need for cost-effective data center interconnects.
Conclusion
Although fiber optic cables have many advantages than copper cables, such as low cost, great bandwidth, high speed and long reach, good reliability and perfect security, copper cables have their unique applications. Generally, copper solutions provide savings of 50% or more compared to optical alternatives for short-range requirements. They can also allow switch makers to utilize open architecture and give end users the choice between expandable copper or optical products. With the improvement of copper technology, copper can also be widely used as fiber optic cables.
