Cabletron Systems TRXI-24 - Manual (Page 18)

REQUIREMENTS/SPECIFICATIONS
Page 2-7
2.1.4 Multimode Fiber Optic Cable Specifications for the
TPIM-F2
Table 2-6 shows Multimode Fiber Optic Cable specifications for the
TPIM-F2.
Maximum Trunk Lengths
The maximum trunk cable length between the TRXI and another
active device is equal to the maximum drive distance as shown in
Table 2-6. When the neighboring token ring device is a passive device,
the combined length of twice the longest trunk cable plus the longest
lobe cable attached to the passive ring segment cannot exceed the
Maximum Drive Distance Trunk Length.
Attenuation
The fiber optic cable must be tested with a fiber optic attenuation test
set that is adjusted for an 850 nm wavelength. This test verifies that
the signal loss in a cable is within an acceptable level. Table 2-6 shows
the attenuation for each Multimode cable type.
Fiber Optic Budget
When determining the maximum fiber optic cable length, the fiber
optic budget delay 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.
Table 2-6. Multimode Fiber Optic Cable Specifications
Cable Type Attenuation Maximum Drive Distance
50/125
µ
m 13.0 dB or less The maximum allowable fiber op-
tic cable length is 2 km (2187.2
yards). However, IEEE 802.5
specifications allow for a maxi-
mum 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