Based on the strings output, I'm guessing that these are Hikvision DVRs. Another problem with these things is that you can only set the admin/root password to

Based on the strings output, I'm guessing that these are Hikvision DVRs. Another problem with these things is that you can only set the admin/root password to a numeric pin through the normal UI and if you use passwd to change it to something reasonable it becomes impossible to log in through the normal UI. Also most users have no idea what telnet is or that there DVR is running it. These things should really be put on an isolated network/VLAN, but again their target customers typically have no idea about those things.