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Siemens Industrial Ethernet Switches SCALANCE X-200 User Manual

Page 64

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Product properties

3.12 SCALANCE XF206-1

SCALANCE X-200

64

Operating Instructions, 12/2011, A5E00349864-19

Autonegotiation

Autonegotiation means the automatic detection of the functionality of the port at the opposite

end. Using autonegotiation, repeaters or end devices can detect the functionality available at

the port of a partner device allowing automatic configuration of different types of device. With

autonegotiation, two components connected to a link segment can exchange parameters

and set themselves to match the supported communication functionality.

Note
If an IE switch port operating in autonegotiation mode is connected to a partner device that is

not operating in autonegotiation mode, the partner device must be set permanently to half

duplex mode.
If an IE switch port is set permanently to full duplex, the connected partner device must also

be set to full duplex.
If the autonegotiation function is disabled, the MDI/MDI-X autocrossover function is also

inactive. This means it may be necessary to use a crossover cable.

Note
The SCALANCE XF206-1 is a plug-and-play device that does not require settings to be

made for commissioning.

MDI / MDIX autocrossover function

The advantage of the MDI / MDIX autocrossover function is that straight-through cables can

be used throughout and external Ethernet crossover cables are unnecessary. This prevents

malfunctions resulting from mismatching send and receive wires. This makes installation

much easier for the user.
IE Switches X-200 support the MDI / MDIX autocrossover function.

NOTICE

Please note that a direct connection of two ports on the switch or an accidental connection

across several switches causes a forbidden loop. Such a loop can lead to network overload

and network failures.

Auto polarity exchange

If the pair of receiving cables are incorrectly connected (RD+ and RD- swapped over), the

polarity is reversed automatically.