Simplex vs. duplex fibre patch cable.

Multimode and single-mode patch cables can be simplex or duplex.

Simplex has one fibre, while duplex zipcord has two fibres joined with a thin web. Simplex (also known as single strand) and duplex zipcord cables are tight-buffered and jacketed, with Kevlar® strength members. Because simplex fibre optic cable consists of only one fibre link, you should use it for applications that only require one-way data transfer. For instance, an interstate trucking scale that sends the weight of the truck to a monitoring station or an oil line monitor that sends data about oil flow to a central location.

Use duplex multimode or single-mode fibre optic cable for applications that require simultaneous, bidirectional data transfer. Workstations, fibre switches and servers, Ethernet switches, backbone ports, and similar hardware require duplex cable.

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Attenuators.