Early J2K DVR's had a VGA connection on the rear panel. It did not pass video unless you added the VGA option. A small VGA board connected to the main board and the VGA connector inside of the DVR. Your DVR may not have this option. To monitor the DVR's video, a TV monitor may be the only option.
Connect the DVR video out to a TV composite video input. This is the yellow RCA jack on most every TV made in the last 10 years. It will be marked AV or Video IN. Next to the yellow RCA will be 2 audio inputs, white and red RCA
jacks. You only need to connect to the yellow video RCA Jack. Select the AV input from your TV's menu, you will then be able to view the DVR.