Cisco Cisco SG200-26P 26-port Gigabit PoE Smart Switch インストールガイド

If you cannot access your switch from the web-based interface, the switch 
may not be reachable from your computer. You can test network 
connections by using ping on a computer running Windows:

Open a command window by using Start > Run and enter cmd.

At the Command window prompt enter ping and the smart switch 
IP address. For example ping 192.168.1.254 (the default IP 
address of the smart switch).

If you can reach the switch, you should get a reply similar to the 
following:

Pinging 192.168.1.254 with 32 bytes of data:

Reply from 192.168.1.254: bytes=32 time<1ms TTL=128

If you cannot reach the switch, you should get a reply similar to the 
following:

Pinging 192.168.1.254 with 32 bytes of data:

Request timed out.

No Power:   

Power up the switch and your computer if they are turned off.

Bad Ethernet connection:   

Check the LEDs for proper indications. Check the connectors of the 
Ethernet cable to ensure they are firmly plugged into the switch and 
your computer.

Make sure that you are using the correct IP address of the switch. You 
can verify the current IP address of the switch with your network 
administrator. The System LED provides an indication of where the 
switch received the IP address, see Section 4 for details.

Make sure that no other device is using the same IP address as the 
switch.

If the switch and your computer are in different IP subnets, you need 
one or more routers to route the packets between the two subnets.