Cabletron Systems HubSTACK SEHI-34 User Manual

Also see for HubSTACK SEHI-34: Addendum

Contents

INSTALLATION REQUIREMENTS/SPECIFICATIONSPage 2-42.1.3 Multimode Fiber Optic Cable Specifications for theEPIM-F1 and EPIM-F2 ModulesTable 2-1 shows Multimode Fiber Optic Cable specifications for theEPIM-F1 and EPIM-F2 modules.AttenuationYou must test the fiber optic cable with a fiber optic attenuation testset adjusted for an 850 nm wavelength. This test verifies that thesignal loss in a cable is within an acceptable level. Table 2-1 shows theattenuation for each Multimode cable type.Fiber Optic Budget and Propagation DelayWhen determining the maximum fiber optic cable length, the fiberoptic budget delay and total network propagation should be calculatedand taken into consideration before fiber optic cable runs areincorporated in any network design.Fiber optic budget is the combination of the optical loss due to thefiber optic cable, in-line splices, and fiber optic connectors.Propagation delay is the amount of time it takes data to travel fromthe sending device to the receiving device. Total propagation delayallowed for the entire network is 25.6 μsec, if the total propagationdelay between any two nodes on the network exceeds 25.6 μsec, thenbridges should be used.Table 2-1. Multimode Fiber Optic Cable SpecificationsCable Type Attenuation Maximum Cable Length50/125 μm 13.0 dB or less The maximum allowable fiberoptic cable length is 2 km(2187.2 yards). However,IEEE 802.3 specificationsallow for a maximum of 1 km(1093.6 yards).62.5/125 μm 16.0 dB or less100/140 μm 19.0 dB or less