Cabletron Systems SEH-34, SEH-32, SEH-24 manual Cable Type Attenuation Maximum Cable Length

INSTALLATION REQUIREMENTS/SPECIFICATIONS

2.1.3Multimode Fiber Optic Cable Specifications for the EPIM-F1 and EPIM-F2 Modules

Table 2-1 shows Multimode Fiber Optic Cable specifications for the EPIM-F1 and EPIM-F2 modules.

Table 2-1. Multimode Fiber Optic Cable Specifications

Cable Type	Attenuation	Maximum Cable Length
50/125 ∝m	13.0 dB or less	The maximum allowable fiber
		optic cable length is 2 km
62.5/125 ∝m	16.0 dB or less
		(2187.2 yards). However,
100/140 ∝m	19.0 dB or less	IEEE 802.3 specifications
		allow for a maximum of 1 km
		(1093.6 yards).

Attenuation

You must test the fiber optic cable with a fiber optic attenuation test set adjusted for an 850 nm wavelength. This test verifies that the signal loss in a cable is within an acceptable level. Table 2-1 shows the attenuation for each Multimode cable type.

Fiber Optic Budget and Propagation Delay

When determining the maximum fiber optic cable length, the fiber optic budget delay and total network propagation should be calculated and taken into consideration before fiber optic cable runs are incorporated in any network design.

Fiber optic budget is the combination of the optical loss due to the fiber optic cable, in-line splices, and fiber optic connectors.

Propagation delay is the amount of time it takes data to travel from the sending device to the receiving device. Total propagation delay allowed for the entire network is 25.6 ∝sec, if the total propagation delay between any two nodes on the network exceeds 25.6 ∝sec, then bridges should be used.

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