The default IP address for management for the AT-8100S series switches is 169.254.1.1/16.
Before connecting the 8100 series switch to the network, connect your PC to one of the switch ports with an Ethernet cable. After the PC has finished its DHCP discovery process you can connect to the web interface of the 8100 at
http://169.254.1.1 using any web browser.
NOTE: Your PC must be set to obtain an IP address via DHCP in order to gain access to the 8100 with its default IP address of 169.254.1.1