2 - 8 ONline Ethernet 10BASE-FL Installation and Operation Guide
Note: The values in Table 2-3 are peak power values. You
determine average optical power by subtracting 3 dBm
from the peak value. All of the examples provided in the
pages that follow refer to peak optical power. Note that
higher optical power is represented by a smaller negative
number (for example, -12 dBm is greater than -20 dBm).
Attenuation
It is possible for receivers to receive too much light when:
❑ Using 85/125 and 100/140 micron fiber cables
❑ Ports are close together on a link
Table 2-3. 10BASE-FL Module Optical Power Budget
Cable Size
Used
(microns)
Transmit
P o w e r
(dBm)
(Peak)
Receive
Power
Range
(dBm) (Peak)
Optical
Power
Budget
(dB)
L i n k L o s s
Required
(dB)
(ONline to
ONline)
50/125
NA 0.20
-16.5 ± 3.0 -8.0 to -29.5 10.0 None
62.5/125
NA 0.275
-12.0 ± 3.0 -8.0 to -29.5 14.5 None
85/125
NA 0.29
-9.0 ± 3.0 -8.0 to -29.5 17.5 >2.0 dB
100/140
NA 0.29
-6.5 ± 3.0 -8.0 to -29.5 20.0 >4.5 dB
