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NOVATEK-ELECTRO
ET-485
Appendix A
Switching to Ethernet
WARNING! Switching the unit to Ethernet network requires mutual coordination of settings on the connected devices.
Connecting the misconfigured unit to the network may affect the communication level of other units on the network. As a rule,
all connections to a network of more than 2 units are carried out by the qualified personnel (network administrator) only.
1.
IP-addressing
When units are communicating over Ethernet network using TCP/IP protocol, every unit is using a set of IP-addressing settings to identify
the sender and receiver of the data. The unit memory contains a personal and unique, within a single subnet, IP-address (four bytes are written as
four integers, separated by dots, in the range of 0-255), subnet mask, which is the same for all units within the subnet (written similar to IP-address),
and IP-address of the gateway, which is used to communicate with other networks. Proper communication between units of a subnet is possible
under several conditions:
1) All units of a subnet have similar mask. Most of small LANs are using 255.255.255.0 mask.
2) Mask starts with a group of bits set to 1, followed by a group of bits turned to 0.
3) All bits set to 1 in the mask are similar for all the IP-addresses of units in subnet and indicate the subnet address. 192.168 is most
frequently used address in LANs for the mask 255.255.255.0. The third byte may be used as a subnet number in a complex LAN. In smaller
LANs, the third byte is usually equal to 0.
4) A set of bits in IP-address of the unit, which is set to 0 in the mask, is unique to each unit within the same subnet .
5) In most cases, the unit like router, which is already communicating with other networks, is switched to the network. This unit often gets the
following address 192.168.0.1, 192.168.0.100, or 192.168.0.101. In this case, other units in the network shall have this IP-address of the
unit as the gateway address. This address is not necessary for communication between units in a subnet, and is only used to connect units
of one subnet to units of other networks.
