Enterasys Networks BRIM-E6 - Manual (Page 37)

CABLE REQUIREMENTS
BRIM-E6 USER’S GUIDE Page 33
Temperature
Multi-pair PVC 24 AWG telephone cables typically have an attenuation
of approximately 8 to 10 dB/100m at 20
°
C (78
°
F). The attenuation of
PVC insulated cable varies significantly with temperature. At
temperatures greater than 40
°
C (104
°
F), we strongly recommend that you
use plenum-rated cables to ensure that cable attenuation remains within
specification.
B.1.2 FOIRL/10BASE-FL Multimode Fiber Optic Cable
Requirements
Table B-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 B-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.
Table B-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