Ubigate iBG2016 Configuration Guide/Ed.00© SAMSUNG Electronics Co., Ltd. 39V.35V.35 is a combination of single-ended and differential synchronous interface.It uses V.35 electrical characteristics for clock and data(differential) andV.28(EIA-232) electrical characteristics for control signals(single-ended).It is typically limited to a maximum throughput of 10Mbps. For the interface,separate clock lines are used for receiving and transmitting data and MRAC-34 connector is used.HSSI InterfaceThe High-Speed Serial Interface(HSSI) is a DTE/DCE interface and isdeveloped to address the need for high-speed communication over WAN links.HSSI defines both electrical and physical interfaces on DTE and DCE devices.It operates at the physical layer of the OSI reference model.The maximum signaling rate of HSSI is 52 Mbps. At this rate, HSSI canhandle the T3 speeds(45 Mbps) of many of today's fast WAN technologies, aswell as the Optical Channel-1(OC-1) speeds(52 Mbps) of the synchronousdigital hierarchy(SDH). In addition, HSSI easily can provide high-speedconnectivity between LANs, such as Token Ring and Ethernet.The use of differential emitter-coupled logic(ECL) helps HSSI achieve highdata rates and low noise levels. ECL has been used in Cray computer systeminterfaces for years and is specified by the ANSI High-Performance ParallelInterface(HIPPI) communications standard for supercomputer LANcommunications. ECL is an off-the-shelf technology that permits excellentretiming on the receiver, resulting in reliable timing margins.HSSI uses a subminiature, FCC-approved 50-pin connector that is smallerthan its V.35 counterpart. To reduce the need for male-male and female-femaleadapters, HSSI cable connectors are specified as male. The HSSI cable usesthe same number of pins and wires as the Small Computer Systems Interface2(SCSI-2) cable, but the HSSI electrical specification is more concise.The flexibility of the HSSI clock and data-signaling protocol makes user(or vendor) bandwidth allocation possible. The DCE controls the clock bychanging its speed or by deleting clock pulses. In this way, the DCE canallocate bandwidth between applications. For example, a PBX may require aparticular amount of bandwidth, a router another amount, and a channelextender a third amount. Bandwidth allocation is key to making T3 and otherbroadband services affordable and popular.
