Verifying Maximum Attenuation For Mixed Fibers; Example; Using Unkeyed Single Mode Cables - 3Com CoreBuilder 2500 Getting Started Manual

Verifying Maximum Attenuation for Mixed Fibers

If you mix Category 1 and Category 2 receivers and
transmitters, use Table D-7
attenuation for each possible combination.
Table D-7 Acceptable Cable Plants for Combinations of
Category 1 and Category 2
Output Input
Category Category
1 1
1* 2*
2 1
2 2
*This combination is dispersion-limited rather than
loss-limited. The expected maximum length is approximately
35 km.

Example

If a Category 2 transmitter is outputting to a
Category 1 receiver, the maximum attenuation is
26.0.

Using Unkeyed Single Mode Cables

The SMF-PMD standard specifies that keyed single
mode connectors must be used with single mode
cables. Figure D-1
single mode connector.
to verify the maximum
Minimum Maximum
Loss Attenuation
0.0 10.0
1.0 16.0
14.0 26.0
15.0 32.0
shows a cross-section of a keyed
Single Mode Fiber Standards
Molded single mode key
Figure D-1 Keyed Single Mode Connector
Because of the limited availability of these keyed
connectors, however, you must be able to get only
those cables with unkeyed connectors.
shows a cross-section of an unkeyed single mode
connector.
Figure D-2 Unkeyed Single Mode Connector
If you are using unkeyed single mode cables, you
can modify the transceiver and connector housing
so that they fit together. Follow these instructions.
The following procedure reverses the transmit and
receive fiber bundles. Be sure to make a
corresponding reversal at the opposite end of the
cable.
D-7
Front of connector
Figure D-2