Working With Fast Ethernet − Automatic Switchover - Siemens CP 443-1 Manual

10 Further Notes on Operation
10.2 Working with Fast Ethernet − automatic switchover
How Autosensing and Autonegotiation Works
On all 4 ports, the CP has a 10/100 Mbps full duplex interface with autosensing
and autonegotiation of the network settings. After turning on the CP, these
functions work as explained below:
S The CP attempts to detect the transmission rate used by the partner.
S If detection is possible, the CP attempts to negotiate an optimum duplex mode
with the partner.
S If no negotiation is possible, the CP uses the previously detected transmission
rate and half duplex.
These steps take approximately 2 seconds.
Automatic Setting or Individual Network Settings
As default, the CP is configured for automatic detection. As soon as you define a
configuration manually when configuring the CP with STEP 7/HW Config (in the
properties dialog of the CP − "Port Parameters" tab), the automatic switchover is
no longer effective. This also applies to the autocrossing mechanism described
below.
Autocrossing Mechanism
With the autocrossing mechanism integrated in the switch, it is possible to use a
standard cable to connect the PC/PG. A crossover cable is not necessary.
Notice
Manual configuration
If a port is set to manual configuration, the autocrossing mechanism is also
deactivated for this port. The port then behaves like the interface of a switch. In
this case, the following applies:
S
Connecting a DTE
To connect a DTE that does not have the autocrossing mechanism (for
example CP 443−1 with order number 6GK7 443−1EX11−0XE0), you must not
use a crossover cable.
S
Connecting to a switch
To connect a switch, that does not support the autocrossing mechanism, use a
crossover cable.
B4A−62
CP 443-1 Advanced for Industrial Ethernet / Manual Part B4A
Release 01/2007
C79000-G8976-C193-06