REQUIREMENTS/SPECIFICATIONS
2-2
•
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 fiber cable segment.
-
16.0 dB or less for 62.5/125 fiber cable segment.
-
19.0 dB or less for 100/140 fiber cable segment.
•
Budget and Propagation Delay
- When determining the
maximum fiber optic cable length, the fiber optic budget delay
and total network propagation should be calculated and taken
into consideration before fiber optic cable runs are incorporated
in any network design. Fiber optic budget is the combination of
the optical loss due to the fiber optic cable, in-line splices, and
fiber optic connectors. Propagation delay is the amount of time
it takes a packet to travel from the sending device to the
receiving device.
•
Length
- The maximum allowable fiber optic cable length is
2 km.
2.3
OPERATING SPECIFICATIONS
This section describes the operating specifications for each of the
fiber optic token ring concentrator modules. Cabletron Systems
reserves the right to change these specifications at any time without
notice.
2.3.1
Ring Speed
The concentrator module ring speed can be set to default to either 4
Mbit/s or 16 Mbit/s. The ring speed is automatically set to a default
setting at power on. The default ring speed can be selected by
positioning a network speed jumper on the board (Refer to Chapter
3,
Installing the Concentrator Module
, to learn how to set the
network speed jumper.) The default setting can be overridden by
changing the ring speed through local or remote network
management software.
