10Gbps rack-to-rack copper interconnects of up to 30 metres have been demonstrated by UK chip-maker Phyworks, using technology it originally developed for the optical module market. The equalisation and clock and data recovery (CDR) capabilities of its PHY2060 IC have been successfully applied to active serial copper cable assemblies which are currently being trialled by cable and connector OEMs. The complete 10G assembly achieves error free transmission at a latency of just 120ns over 30m of 24AWG twin-ax copper cable.
Under pressure to support a far wider range of voice, video and data services while keeping capital expenditure down, data centre operators are looking for new ways to connect up systems that are low in cost and power and yet which ensure minimum latency and maximum possible quality of service. Able to be integrated into incumbent XFP and emerging SFP+ ports, the PHY2060 IC enables new copper cable interconnects to be hot-plugged into existing optical ports providing data centre operators with greater flexibility.
10G inter-rack connections up to 30 metres have traditionally depended on 10GBASE-SR optical modules and 10GBASE-CX4 copper cable. In the XFP connector format, a pair of 10GBASE-SR optical modules costs around $400-600 USD while a substitute active serial copper cable assembly is predicted to cost around $150-200 USD.
40% smaller in cross section and 30% lighter, twin-ax copper cable is far less bulky than CX4 and at $1USD per metre compared to CX4’s $7USD per metre is significantly more cost effective. In addition, CX4’s need for line-card mounted quad re-timers and quad pre-emphasis drivers and the PCB space to support 8 data lanes adds considerable overhead.
