Cabletron Systems SEH-34 - Manual (Page 17)

INSTALLATION REQUIREMENTS/SPECIFICATIONS
Page 2-5
2.1.4 Single Mode Fiber Optic Cable Specifications for
the EPIM-F3 Module
Table 2-2 shows Single Mode Fiber Optic Cable specifications for the
EPIM-F3.
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
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 2-2. Single Mode Fiber Optic Cable Specifications
Cable Type Attenuation Maximum Cable Length
8/125-12/125
µ
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).