User`s guide

Chapter 2: Network Planning and Configuration
Page 2-2 IRM3 User’s Guide
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.
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 µm fiber optic cabling
- 62.5/125 µm fiber optic cabling
- 100/140 µm 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 µm fiber cable segment
- 16.0 dB or less for 62.5/125 µm fiber cable segment
- 19.0 dB or less for 100/140 µm fiber cable segment
NOTE
The SQE function is used to confirm that the collision signaling
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.