if you are accessing from remote machine on public network then you need to connect your ELB-REV4 to your home router which has static ip address login to your router page an assign a port which is higher than 1200 to your ELB-REV4. and then you can ssh -p <port number> root@static_ipaddress
if you are accessing the device on a local LAN network then ssh -p 22 [email protected] here 192.168.1.178 represent IP address assigned to your ELB-REV4.