Cabletron Systems SEH-24, SEH-32, SEH-34 manual Installation REQUIREMENTS/SPECIFICATIONS

INSTALLATION REQUIREMENTS/SPECIFICATIONS

2.1.4Single Mode Fiber Optic Cable Specifications for the EPIM-F3 Module

Table 2-2 shows Single Mode Fiber Optic Cable specifications for the EPIM-F3.

Table 2-2. Single Mode Fiber Optic Cable Specifications

Cable Type	Attenuation	Maximum Cable Length
8/125-12/125 ∝m	10.0 dB or less	The maximum allowable fiber
		optic cable length is
		5 km (3.1 miles) with bridges
		at each segment end. Howev-
		er, IEEE 802.3 FOIRL specifi-
		cations specify 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 1300 nm wavelength. This test verifies that the signal loss in a cable is 10.0 dB or less for any given single mode fiber optic link.

Fiber Optic Budget and Propagation Delay

Fiber optic budget is the combination of the optical loss due to the fiber optic cable, in-line splices, and fiber optic connectors. When determining the maximum fiber optic cable length, the fiber optic budget (total loss of 10.0 dB or less between stations) and total network propagation delay should be calculated and considered before fiber optic cable runs are incorporated in any network design.

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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