Cabletron Systems SEH-34 - Manual (Page 16)

INSTALLATION REQUIREMENTS/SPECIFICATIONS
Page 2-4
2.1.3 Multimode 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.
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
µ
sec, if the total propagation
delay between any two nodes on the network exceeds 25.6
µ
sec, then
bridges should be used.
Table 2-1. Multimode Fiber Optic Cable Specifications
Cable Type Attenuation Maximum Cable Length
50/125
µ
m 13.0 dB or less The maximum allowable fiber
optic cable length is 2 km
(2187.2 yards). However,
IEEE 802.3 specifications
allow for a maximum of 1 km
(1093.6 yards).
62.5/125
µ
m 16.0 dB or less
100/140
µ
m 19.0 dB or less