IEEE802.3 Ethernet supports the auto negotiation
speed function to get suitable speeds. However, for
connecting to some switches/hubs, the communication
speed must be fixed at 100 Mbps or 10 Mbps. Users can
use this function to fix the communication speed.
Note: NPort 6250-S-SC, 6250-M-SC only accept setting
as 'auto-Negation'.