Fiber Optic Port Requirements - Cabletron Systems IRM-3 User Manual

Chapter 2: Network Planning and Configuration
When connecting a network segment to the IRM3 through a transceiver
and an AUI cable, the following requirements must be met:
• The transceiver to which the IRM3 will be connected must meet
Ethernet Version 1, Version 2 or IEEE 802.3 standards.
• The AUI cables connecting the IRM3 to the transceiver on the network
must be IEEE 802.3 type cables and must not exceed 50 meters in
length.
• The Signal Quality Error (SQE) function on the transceiver must be
disabled.
The SQE function is used to confirm that the collision signaling
NOTE
of the transceiver is working properly. However, when
connecting a transceiver to the IRM3, or any other repeater,
you must disable the SQE test function. If SQE is not disabled,
the repeater regards each SQE signal as a collision and
resends the JAM packet, causing a considerable slowdown of
network operations.

2.1.3 Fiber Optic Port Requirements

When connecting a Fiber Optic Link Segment to the IRM3 fiber optic ST
ports, the following requirements must be met:
• Cable Type - The fiber optic link segment should consist of one of the
following:
- 50/125 m fiber optic cabling
- 62.5/125 m fiber optic cabling
- 100/140 m fiber optic cabling
• Attenuation - The fiber optic cable must be tested with a fiber optic
attenuation test set that is adjusted for an 850 nm wavelength. This test
verifies that the signal loss in a cable is within an acceptable level:
- 13.0 dB or less for 50/125 m fiber cable segment
- 16.0 dB or less for 62.5/125 m fiber cable segment
- 19.0 dB or less for 100/140 m fiber cable segment
Page 2-2 IRM3 User's Guide