363-206-305
Technical Specifications
10-38
Issue 3 June 2000
Table 10-19 details the maximum link budgets for each pairing of OC-3 rate OLIUs
when operating on multimode (MM) fiber. These numbers give the maximum
attenuation acceptable for proper operation of each transmitter/receiver pair. The
link must have no more than this much attenuation either from fiber loss, splice
loss, connector loss, external attenuators or a combination of these or the link will
not operate properly. The maximum link budgets for MM fiber were calculated
using the following margins. The first column of margins applies to any link where
there is at least one OC-3 OLIU (28G-U/28G2-U, 22F-type or 22G-type). The
second column of margins applies to links having two IS-3 (22D-U) OLIUs.
NOTE:
The maximum link budget is not always symmetrical. A transmitter/receiver
pair may have one maximum link budget in one direction and another in the
opposite direction. For example, a 28G-U transmitting to a 22F has a
maximum MM link budget of 22.0 dB. In the opposite direction, though, a
22F transmitting to a 28G-U has a maximum MM link budget of 12.0 dB. Be
careful of this asymmetry when planning and engineering a link having
mixed OLIUs.
Table 10-19. . OC-3 Rate OLIU Mixes - Maximum Link Budgets for MM Fiber
(dB)
At Least One
OC-3 OLIU
IS-3 OLIUs
Only
MM Optical Path Penalty (dB)
Connector Loss (dB)
Unallocated Margin (dB)
4.0
1.5
1.5
1.6
1.5
2.0
Transmitter
Receiver
22F/
22F-U/
22F2-U
22G-U/
22G2-U/
22G3-U/
22G4-U
28G-U/
228G2-U
22F/22F-U/22F2-U
22G-U/22G2-U
22G3-U/22G4-U
28G-U/28G2-U
12.0
20.0
22.0
22.0
12.0
20.0
22.0
22.0
12.0
20.0
22.0
22.0
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