100Base-Fx (Multimode); Cable Type; Attenuation; Insertion Loss - Cabletron Systems 100BASE-FX Cabling Manual

100BASE-FX (Multimode)

All Cabletron Systems 100BASE-FX products require that installed facility cabling
and cable hardware meet the following minimum specifications. If a network
cabling installation is not within the limitations presented here, the operation of
the 100BASE-FX products may be affected.

Cable Type

Cabletron Systems 100BASE-FX network devices require specific types of cabling.
100BASE-FX multimode fiber optic devices manufactured by Cabletron Systems
are able to support connections to and from the following types of multimode
fiber optics:
•
•
•

Attenuation

Multimode fiber optic cables must be tested for attenuation with a fiber optic
attenuation test set. The test set must be configured to determine attenuation of
the cable at a wavelength of 850 nm. The attenuation test will confirm or deny that
the cable falls within an acceptable level. The acceptable level of attenuation for a
100BASE-FX cable is 11.0 dB.

Insertion Loss

The 100BASE-FX specification allows for a total dB loss of 10 dB or less between
any two stations or devices connected by fiber optic cabling. When calculating
insertion loss, you must consider and count any loss introduced by fiber optic
splices, barrel connectors, distribution boxes or other cable management devices.
The typical dB loss for a splice or a connector is less than 1 dB. The loss statistics
for any fiber optic cable management hardware should be available from the
manufacturer.

Delay

As fiber optic cabling is often used to make connections between Fast Ethernet
repeaters or hubs, the 100BASE-FX specification allows a multimode fiber optic
link to be configured such that the total propagation delay for the link is less than
or equal to 2.56 s one-way. Keep in mind, however, that propagation delay must
be calculated for the entire network. If there are more stations than the one
connected by your fiber optic link, you must also calculate the propagation delay
for the longest of those station links.
100BASE-FX (Multimode)
50/125 m
62.5/125 m
100/140 m
Full-Duplex Fast Ethernet Network Requirements
8-5