Optical cable fiber specifications

Learn about the optical fiber cable specifications for your server.

The preferred optical fiber for the server is 50/125 multimode fiber. This is because its bandwidth is a factor of three higher than 62.5/125 at the 780 nm wavelength at which the system operates. The 62.5/125 multimode fiber is also supported but at reduced distances. For 3xx systems at 220 Mbps and 5xx, 6x0, Sx0, and SB1 servers at 266 Mbps, a 50/125 fiber will support a distance of 2000 meters. A 62.5/125 fiber will support a distance of 700 meters.

For 5xx, 6x0, Sx0, and SB1 systems that use the higher speed 1063 Mbps link, optical technology with 50/125 fiber will support a distance of 500 meters. A 62.5/125 fiber will support a distance of 175 meters.

Care should be taken so that optical fiber cables are not coiled to a diameter less than 16 cm (6.3 in) and not bent to a radius less than 3 cm (1.2 in). Do not grip optical cables with mechanical tools.

More information about optical cable installation can be found in 940x Installation and Upgrade, SY44-5950.

Note: Although optical technology will support these distances, not all functions can operate at those distances in all cases. Review disk unit and tape unit operation functions before supporting distances beyond 100 meters.

Cable specifications for 50/125:
 
Bandwidth:
400 MHz-km at 780 nm. This is equivalent to 500 MHz-km at 850nm.
Attenuation:
4.0 dB/km at 780 nm. This is equivalent to 3.0 dB/km at 850nm.

 

Cable specification for 62.5/125:
 
Bandwidth:
160 MHz-km at 850 nm.
Attenuation:
4.0 dB/km at 850 nm wavelength.

Depending on the data rate, the allowable link loss available to the user varies from 6 to 12 dB. Typical optical fiber connectors have a loss of 0.2 dB with a 0.5 dB maximum loss, and splices run 0.1 to 0.3 dB loss.

Connectors for 3xx systems:
The connections to the optical ports of I/O Bus Expansion are SC duplex connectors. The jumper cables available with the server when shipped are duplex cables. These cables terminate with SC duplex connectors with a PC polish. Use the simplex ST connectors for the system power control network (SPCN).
Connectors for 5xx, 6x0, Sx0, and SB1 systems:
The connector used for the 266 and 1063 data rate is slightly different than that used on the 220 Mbps links. For 3xx, a duplex SC connector is used. The 5xx, 6x0, Sx0, and SB1 machines have been changed to conform to industry standard Fiber Channel Support (FCS) duplex SC connector. The FCS SC connector is similar in appearance to the 3xx duplex SC connector but the keying orientation is different. The FCS duplex connector used for 5xx, 6x0, Sx0, and SB1 also employs two SC connectors joined together but the two SC connectors are rotated 90 degrees from the connectors used on 3xx systems.