Unfortunately, it is best to assume that you cannot use your
old surveillance cameras. Suveillance cameras used in a digital system must be of a reasonably high quality. A poor camera that does not have a strong
S/N will result in poor video and will require a much larger amount of disk space to store video. The noise in the video signal is often not recognized as noise and thus the system works very hard to record all of the noise and thus results in the systems hard disk filling up with very large files.
