100Base-Fx - Siemens SCALANCE X-400 Operating Instructions Manual

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