Siemens X-400 ユーザーズマニュアル

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System Description of SCALANCE X-400 
Operating Instructions for SCALANCE X-400 Industrial Ethernet Switches 
C79000-G8976-C186-03 
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2.2.3 100Base-FX 
Transmission Rate 
The transmission rate of the optical fast Ethernet ports is 100 Mbps. 
Transmission Mode 
Transmission with 100Base-FX is defined in the IEEE 802.3u standard and is 
specified as 100 Mbps transmission rate and full duplex. 
Transmission Medium 
Data transmission is over multimode or single mode fiber-optic cable (FOC). The 
wavelength is 1310 nm. 
Two FOC types can be used: 
● Multimode FOC 
The core diameter is 50 µm; the light source is an LED. Many modes (light 
beams) are used for signal transmission. The propagation times of the light 
pulses (dispersion) restrict the maximum range considerably. 
●  Single mode FOC 
The core diameter is 9 or 10 µm; the light source is a laser diode. To transmit a 
signal, only one mode (light beam) is used greatly reducing dispersion. As a re-
sult, the maximum range of single mode FOC is greater than that of multimode 
FOC. 
Regardless of the type used, the outer diameter of the FOC is 125 µm.