Siemens X-400 - Manual (Page 27)

System Description of SCALANCE X-400
Operating Instructions for SCALANCE X-400 Industrial Ethernet Switches
C79000-G8976-C186-03
27
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.