From http://www.lliures.org/2008/05/02/ft3563-bt-hacking/, following procedures are my experiencing of access NSD-100 using telnet program.
1.Connect external USB HDD to NSD-100 and enter web control (login:admin/password:root) to format as XFS.
2. Turn-off NSD-100, and connect external USB HDD to PC (use Linux to access partitions.) via USB cable.
3. Edit smb.conf, and add below line what you created into [public] :
root preexec = /mnt/data/public/bd
4. Create script file “bd” into folder “public” and type below content for access NSD-100 using telnet.
echo "pts/0" >> /etc/securetty
5 change script file “bd” permission to 755 (# chmod bd 755)
6. Re-connect external USB HDD to NSD-100 and using PC (windows) access folder “public” of external USB HDD via workgroup.
7. Now, you can access NSD-100 via telnet program, like pietty … successfully.