Tenda TFC100A — 100mbps Single Mode Media Converter

Buying it, and when not to

The TFC100A is a 100Mbps single-mode media converter. It converts between fibre and copper Ethernet - fibre in, Ethernet out, or the reverse - and it is the small, dull component that makes long runs possible.

Copper Ethernet stops at about a hundred metres. Fibre does not. Whenever a link has to cross more than that - between two buildings on a compound, up a tall building, from a gatehouse to a main house, across a market to another block, or out to a mast - a pair of media converters and a single-mode fibre is how the connection is made. Single-mode in particular is the right choice for distance. Buy them in pairs: one at each end of the fibre.

They are also the correct answer to electrical isolation, which matters more in Nigeria than the specification sheets admit: a fibre run between two buildings on different earths carries no surge, so a lightning strike or an inverter fault on one side does not destroy the switch on the other. Where a switch already has an SFP slot - the TEG1110PF, TEG1120P, TEG1128P and TEG2200-series units all do - use an SFP module directly instead and skip the converter entirely; it is tidier and one less box to power. And note the 100Mbps rating: for a link that needs to carry gigabit traffic, this is the wrong converter.