11-17
Cisco Network Modules Hardware Installation Guide
OL-2485-20
Chapter 11 Connecting ATM Network Modules
ATM OC-3 Network Modules
The following example of a single-mode power margin assumes these values:
•
Power budget 16 dB (SONET worst-case specification for SMI)
•
Two buildings 8 kilometers apart
•
Connections through a patch panel in an intervening building with a total of 12 connectors
PM = PB – LL
= 16 dB – 8 km x (0.5 dB/km) – 12 x (0.5 dB)
= 6 dB
The positive value means this link should have enough power for transmission.