ray said
I am taking over someone else's work. The existing cameras are wired with a siamese cable I've not seen before. It looks like zip cord or lamp card with molded connectors at each end. I believe it is the pre-made cables i've seen advertised. I plan on replacing what I have access to. Some of it is buried in walls.  Can use of this cable effect the quality of the image?  What is the recommended method of splicing. It has several taped splices at this time. Should I splice at the existing connectors? HELP!!!

If its Plug and play cable I strongly suggest not to splice it as well as not to use it in situations where you can use a better grade cable like Normal Siamese cable. 

Plug N' Play Cable 

ray said
I believe you are correct it looks like plug & play cable. I do plan on replacing what I can.  What is my best alternative where I can't replace the existing cable. What are my alternatives re: existing splices.

The problem with Plug and Play cable is that you cannot add a BNC connector as the center conductor is stranded instead of Solid. I would use pull string cut the end of the plug and play cable and attach the pull string to it tightly use the existing Plug and play cable to pull the pull string through and pull the Siamese using the pull wire.