Siemens SCALANCE X-300 Configuration Manual page 336

PROFINET IO functionality
6.2 Settings in HW Config
Figure 6-12
Settings made during configuration
The transmission rate of the port can be set to Autonegotiation or fixed, for example, at 100
Mbps full duplex.
Note
If you select a fixed speed and duplexity, you need to set the check mark for "Disable
autonegotiation".
336
Properties - RJ-45 Gigabit Ethernet port options
Configuration Manual, 10/2014, C79000-G8976-C187-22
SCALANCE X-300 / X-400