Redvee

I have an old existing Tekvision 720P HD DVR with 4 Tekvision 720P cameras which is working fine, quality is ok, not great, but fine for what I needed. I recently got two Yale 1080p cameras which I thought I could use with existing DVR to expand the system (clearly I'm no expert). They do work when I connect them to the DVR, however no colour, only B&W. Is it possible to adjust the system settings to get the 1080p cameras to work alongside the 720p or are they just not compatible with the existing DVR / system? Any help would be appreciated as I'm out of my depth here.

Thanks, that sounds like it could be the issue alright - makes sense to get a new DVR - the DVR I have has 8 inputs, so I thought I could just plug in 2 extra cameras, but clearly noy. I didn't want to replace the old cameras, because they're Ok and mainly to be honest because getting up to the eaves to access to replace them is difficult. Thanks again for the advice ?