IBM 8265, Site Preparation Manual

Page: 41 / 164

Chapter 4. Planning for Fiber Connections
25
Optical Fiber Cable Specifications
The IBM Cabling System currently recommends 100/140-micron optical fiber for
extending token-ring transmission distances between wiring closets. But IBM now
recommends the 62.5/125-micron optical fiber for most establishment cabling
applications. The 100/140-micron optical fiber will continue to be supported for token-
ring networks and fiber distributed data interface (FDDI) networks.
The 62.5/125-micron fiber specification is patterned after the fiber specification in the
emerging Commercial Building Wiring Standard (developed by the TIA 41.8.1, and
under study by the ISO SC25/WG2 working groups) which will meet most of the intra-
building and campus link requirements. This specification is expected to become the
accepted multimode standard for government and commercial buildings and meet the
ATM and FDDI application requirements. The FDDI standard also provides the
information for attaching FDDI cable using 50/125-, 100/140-, or 85/125-micron
multimode optical fibers. IBM recommends 62.5/125-micron multimode optical fiber.
IBM also supports 50/125- (preferred in Japan and other countries), 85/125-, and
100/140-micron multimode optical fibers, as defined in the ISO 9314/ANSI X3T9.5
standard for both the token-ring networks and FDDI applications.
Each cable specification parameter must be met over the full range of operating
temperatures. A suggested temperature range of 0
°
C - 52
°
C (32
°
F - 125.6
°
F) is an
appropriate choice for many installations. Maximum summer and minimum winter
temperatures may differ from this range, particularly in installations where fiber cable
will be installed in uninsulated and unheated areas (typically building attics).
Customers should select a grade of fiber that will perform to specification in those
instances where the temperature may exceed the suggested range.
Recommended Optical Fiber Specifications for Commercial Building Wiring
Multimode Optical Fiber Cable
Table 16. Multimode Optical Fiber Cable Specifications
Description 62.5/125 50/125
Core diameter
Cladding diameter
Numerical aperture
Core/cladding offset
Core non-circularity
Cladding non-circularity 62.5 +/-3
µ
m
127 + 0/-4
µ
m
0.275 + /-0.015
3
µ
m (maximum)
6% (maximum)
2% (maximum)
50 + /-3
µ
m
127 + 0/-4
µ
m
0.2 + /-0.015
3
µ
m (maximum)
6% (maximum)
2% (maximum)
Maximum Attenuation at wavelength
850 nanometers
1300 nanometers 3.75 dB/km
2.0 dB/km
3.5 dB/km
1.5 dB/km
Minimum Bandwidth at wavelength
850 nanometers
1300 nanometers (wiring closet to office)
1300 nanometers (channel extension application) 160 MHz
500 MHz
500 MHz 500 MHz
500 MHz
800 MHz