Maintaining Network Integrity One important feature for a copper extension product could be to maintain the network integrity. This ensures that the network speed (wire speed) of the link is maintained at either 100Mbps or 10Mbs and that the connection is fully symmetrical. By doing this it is possible to integrate units into an Ethernet network with complete confidence that the links in no way degrades the performance of the network as they operate at the chosen wire speed. It should also be added at this stage that the line speed selected does not have to be the data rate your traffic must pass at but rather the maximum data rate that the transmission path will support. The ComNet CopperLine range operates in this very way and supports extended distance transmission over either coaxial or twisted pair cable, with the coaxial medium specified at RG59 or better and the twisted pair CAT5 or better. At 100Mbps distances extend to over six hundred meters on the minimum grade cable and if data rates are set to 10Mbps distances can be up to fifteen hundred meters on RG59 coaxial cable. The coaxial cable solution provides a simple migration path for analogue end users with legacy coaxial installations who can run their new IP systems over the existing installed infrastructure. It is fundamental to the successful operation of the system that the cable parameters and quality meets or exceeds the type stipulated by Comnet. CAT5 cable must meet the ANSI/TIA/EIA-568 standard and RG59 coaxial should be of a quality construction. Standards in coaxial cable can be many and varied and care should always be taken when looking to operate across it. Along with the data CopperLine also provides support for PoE at either the 15.4W (IEEE802.3af ) or the 30W (IEEE802.3at) power levels 1 . Unfortunately passing power through copper cables is governed by the laws of physics 2 and there is an inverse relationship between the distance and the power level that can be maintained across the link. At the 15.4W level CopperLine operates in a pass-through mode, where the devices outside of the CopperLine units (in the example below an Ethernet switch and IP camera) function as the PSE (Power Sourcing Equipment) and PD (Powered Device) respectively. CopperLine units can either be externally powered or via the PSE.