Siemens SIMATIC NET SCALANCE X-100 Series Operating Instructions Manual page 33

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
Devices not supporting autonegotiation must be set to 100 Mbps half duplex or 10 Mbps half
duplex.
Note
The SCALANCE X116 is a plug-and-play device that does not require settings to be made
for commissioning.
Auto polarity exchange
If the pair of receiving cables are incorrectly connected (RD+ and RD- swapped over), the
polarity is adapted automatically.
MDI /MDIX autocrossover function
The advantage of the MDI /MDIX autocrossover function is that straight-through cables can
be used throughout and crossover Ethernet cables are unnecessary. This prevents
malfunctions resulting from mismatching send and receive wires. This makes installation
much easier for the user.
The devices of the SCALANCE X-100 product line all support the MDI / MDIX autocrossover
function.
NOTICE
Please note that the direct connection of two ports on the switch or accidental connection
over several switches causes an illegal loop. Such a loop can lead to network overload and
network failures.
SCALANCE X-100
Operating Instructions, 04, A2B00060666D
Product properties
3.9 SCALANCE X116
33