Cabletron Systems NBR-620, NBR-420, NBR-220 manual C.1.2 Multimode Fiber Optic Network

Network Cable Requirements

•Temperature - Multi-pair PVC 24 AWG telephone cables typically have an attenuation of approximately 8-10 dB/100 m at 20°C (68°F).

The attenuation of PVC insulated cable varies significantly with temperature. At temperatures greater than 40°C (104°F), we strongly recommend using plenum-rated cable to ensure attenuation remains within specification.

C.1.2 Multimode Fiber Optic Network

When connecting a multimode fiber optic link segment to an EPIM-F1 or EPIM-F2, ensure the network meets the following requirements:

•Cable Type - Use the EPIM-F1 and EPIM-F2 for the following multimode fiber optic media:

-50/125 ∝m fiber optic cabling

-62.5/125 ∝m fiber optic cabling

-100/140 ∝m fiber optic cabling

•Attenuation - You must test the fiber optic cable with a fiber optic attenuation test set adjusted for an 850 nm wavelength. This test verifies the signal loss if a cable falls within the following acceptable levels:

-13.0 dB or less for a 50/125 ∝m fiber cable segment

-16.0 dB or less for a 62.5/125 ∝m fiber cable segment

-19.0 dB or less for a 100/140 ∝m fiber cable segment

•Budget and Propagation Delay - When you determine the maximum fiber optic cable length to incorporate fiber runs into your network, you must calculate and consider the fiber optic budget (a total loss of

10.0 dB or less is permissible between stations) and total network propagation delay.

-To determine the fiber optic budget, combine the optical loss due to the fiber optic cable, in-line splices, and fiber optic connectors. Typical loss for a splice and connector (together) equals 1 dB or less.

NBR-SERIES Installation Guide Page C-3