Ethernet Network Adapter Installation Guide

MAKING NETWORK CONNECTIONS
Page 3-7
Verify that the fiber strands are “crossed over” at the far end
device, transmit to receive, by checking the labeling on each
strand. Verify that the fiber connection meets the dB loss
specifications outlined in Section 3.3.1, below. If a link still has not
been established, contact Cabletron Systems Technical Support
(see Section 2.12, Getting Help).
1
2
1. ST Port
2. ST Connector
Figure 3-4. ST Fiber Optic Connectors
3.3.1 Fiber Optic Requirements
• Cable - The fiber optic link segments should consist of either
50/125 µm, 62.5/125 µm, or 100/140 µm fiber optic cabling.
• Attenuation - Cable must be tested with a fiber optic
attenuation test set adjusted for an 850 nm wave length. This
test verifies that the signal loss in the cable is acceptable.
Attenuation limits for various cable are listed below:
- 13.0 dB or less for a 50/125 µm fiber cable segment.
- 16.0 dB or less for a 62.5/125 µm fiber cable.
- 19.0 dB or less for a 100/140 µm fiber cable.
• Fiber Optic Budget - the fiber optic budget and total network
propagation delay should be calculated before fiber runs are
incorporated in any network design. Fiber optic budget is the
combination of optical loss of the fiber optic cable, in-line
splices, and fiber optic connectors. Propagation delay is the
time it takes a packet to travel from the sending device to the
receiving device.