Fibre network cables are constructed with a central core, carrying data in the form of light, and a surrounding cladding. Both OM1 and also OM2, which is constructed with a 50um diameter light core, are capable of data transfer rates of up to 1000Mbps. Owing to a narrower light core in the cable design, OM2 provides extension across a greater distance than that of OM1. Because of the difference in core diameter, it is important that the different types are not used within the same system. OM3 is produced using 50um diameter high grade laser optimised fibre cable and is capable of delivering data transfer rates of up to 10Gbps. Completing the range, we have a section dedicated to OS1 singlemode fibre cabling. Employed for fibre links over greater distances than that of which multimode signals are capable, OS1 cables are also suitable for use in systems of up to 10Gbps.