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).

Table 2-3. 10BASE-FL Module Optical Power Budget

Cable Size

Transmit

Receive

Optical

Link Loss

Power

Power

Power

Required

Used

(dBm)

Range

Budget

(dB)

(microns)

(Peak)

(dBm) (Peak)

(dB)

(ONline to

 

 

 

 

 

ONline)

 

 

 

 

 

50/125

-16.5 ± 3.0

-8.0 to -29.5

10.0

None

NA 0.20

 

 

 

 

 

 

 

 

 

62.5/125

-12.0 ± 3.0

-8.0 to -29.5

14.5

None

NA 0.275

 

 

 

 

 

 

 

 

 

85/125

-9.0 ± 3.0

-8.0 to -29.5

17.5

>2.0 dB

NA 0.29

 

 

 

 

 

 

 

 

 

100/140

-6.5 ± 3.0

-8.0 to -29.5

20.0

>4.5 dB

NA 0.29

 

 

 

 

 

 

 

 

 

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

2 - 8 ONline Ethernet 10BASE-FL Installation and Operation Guide

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3Com 5104M-FL1 BASE-FL Module Optical Power Budget, Cable Size Transmit Receive Optical Link Loss Power, DBm, ONline to