on your 770, open xterm and type

netstat -na |grep 22

if you do not see an entry for LISTENING on port 22, then your ssh server is not up. by default, there is no firewall enabled on the tablet. secondly, i am not sure if ssh as root user is allowed. you may need to edit /etc/ssh/sshd_config. look for the entry "PermitRootLogin". if there is a # sign in front of it, the default of yes (or allow) is used.

the options available are yes, no, and without-password. without-password uses key based authentication. yes will allow root to ssh to the device using a password. no will no allow root to ssh to the device at all.