Hey guys.....newbie on the ip camera scene. I inherited a system in an office condo. Its a Backstreet system with POE cameras. The NVR has a POE switch with some extra spaces to add cameras. I don't know how old the NVR is but i've kinda got the interface figured out. It doesn't have but 4 cameras, one of which is dead. I would like to add/replace a couple more. I searched through the threads for info on a backstreet system and the consensus is Backstreet simply rebrands dahua cameras. If this is the case, am I limited to the backstreet or dahua brand only? I'm looking for some help in finding a camera that is compatible with the existing system. My plan is to build/upgrade to a blue iris system when the backstreet NVR takes a dump. It would be great if I could use the new cameras in the new system. I'm not sure what brand or specs to look for so that it will work on the existing system. The camera placement will be at the front entrance door. Any help would be appreciated.