Cisco Systems Cisco 12008 manual Line Card Sonet Signal Requirements

Site Wiring Guidelines

Subtracting the data link loss from the power budget should produce a result greater than zero. If a result is less than zero, you may have insufficient power for receiver operation.

For SONET line cards, the signal must meet the signal requirements listed in Table 2-6.

Table 2-6	Line Card SONET Signal Requirements
Characteristic		Single-Mode	Multimode
Minimum transmitter		–18.5	–15
power (PT)
Minimum receiver		–30	–28
sensitivity (PR)
Power Budget (PB)		–11.5	–13

Multimode Power Budget Example (with Sufficient Power for Transmission)

This section contains a sample calculation of a multimode power budget, based on the following variables:

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Length of multimode link = 3 km

Four connectors

Three splices

Higher order loss (HOL)

Clock recovery module (CRM)

Estimate the power budget, as follows:

PB = 13 dB – 3 km (1.0 dB/km) – 4 (0.5 dB) – 3 (0.5 dB) – 0.5 dB (HOL) – 1 dB (CRM)

PB = 13 dB – 3 dB – 2 dB – 1.5 dB – 0.5 dB – 1 dB

PB = 5 dB

The resulting power budget (PB) value of 5 dB indicates that this link would have sufficient power for fiber-optic transmission.

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