Hirschmann RS20 User Manual page 27

Entering the IP Parameters
The bits of the host address (host id) that represent the mask are set to one.
The remaining bits of the host address in the netmask are set to zero (see
the following examples).
Example of a netmask:
Decimal notation
255.255.192.0
Binary notation
11111111.11111111.11000000.00000000
Example of IP addresses with subnetwork assignment when the above
subnet mask is applied:
UM BasicConfig L2E
Release 8.0 05/2013
Subnetwork mask bits
Class B
2.1 IP Parameter Basics
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